Interactive Global Illumination Using Selective Photon Tracing
Thirteenth Eurographics Workshop on Rendering(2002) P
1.Introduction
Synthesis of realistic images which predict the appearance of the real world has many important engineering applica-tions including product design,architecture and interior de-sign,and illumination engineering.One of the major com-ponents of such predictive image synthesis is global illumi-nation.Even for less rigorous applications such as special effects,?lm production,and computer games global illumi-nation greatly improves the appearance and believability of rendered images.
The vast majority of existing global illumination solutions are designed for off-line computations and for static scenes. The response times required by such solutions to update illumination information in dynamically changing environ-ments are prohibitively large even for minor changes in the scene,because the whole computation is usually repeated from scratch.Some successful attempts have been made to upgrade those algorithms to exploit the temporal coherence and reuse valid lighting information computed previously. While interactivity is often achieved for some simple scene changes,the storage costs involved in the data structure ex-tensions into the temporal domain are intractable for practi-cal applications dealing with complex scenes.
In this paper we propose a novel global illumination tech-nique designed speci?cally for interactive applications.Our algorithm exploits a periodicity property29of the multi-dimensional Halton sequence,which provides immediate in-formation on the similarity of photon paths in the scene. This enables selective photon tracing into the scene regions whose illumination must be updated due to the user interac-tion.To improve the progressivity of such update energy-and perception-based criteria are introduced whose main goal is to minimize the image artifacts as perceived by the observer.The unique feature of our selective photon tracing is that while the temporal coherence in lighting computa-tions is strongly exploited,no additional data structures in-
c The Eurographics Association2002.
volving photon paths in the dynamically changing scene are required.Moreover,since the photon hit points are bucketed on-the-?y directly into the corresponding elements of dense mesh the photon storage is completely avoided.In practice this means that if the mesh data structures required for ef-?cient ray(photon)tracing?t into the computer memory the global illumination computation can be performed using our method.This makes our technique suitable for interac-tive global illumination even for complex scenes.In terms of hardware requirement a simple PC-class computer equipped with a graphics board offers suf?cient performance for our technique,and expensive multiprocessor computers or com-puter clusters are not required.
Our rendering technique is optimized for interactivity and some of its design decisions clearly trade off image qual-ity for computation speed.The most severe limitation of our technique is the use of simple photon bucketing for the mesh-based reconstruction of indirect illumination(direct il-lumination and resulting shadows are rendered using graph-ics hardware).Obviously,by storing photon hit points and using more advanced density estimation techniques15264118 less bias could be obtained but then the rendering interactiv-ity would be compromised.
The paper is organized as follows.Section2reviews the previous approaches to global illumination in dynamic en-vironments.In Section3we introduce our new framework. We discuss the periodicity property of the Halton sequence which is the foundation for our selective photon tracing in Section4.The algorithm of interactive global illumination computation is explained in Section5.In Section6we pro-vide some implementation details of our interactive system. We discuss the results obtained by our techniques in Sec-tion7.Finally,we conclude the paper and propose some fu-ture directions for this research.
2.Previous Work
The problem of global illumination solutions for dy-namic environments has attracted signi?cant attention of re-searchers,resulting in various solutions which can roughly be categorized as off-line or interactive.In the following sec-tion we brie?y overview representative examples of off-line algorithms.Then we focus on interactive algorithms,which are more relevant for this paper.
2.1.Off-Line Techniques
Off-line global illumination algorithms are used in the pro-duction of high quality animations in which the accuracy of lighting simulation cannot be compromised.Many existing solutions resulted from extending hierarchical radiosity al-gorithms into the time domain,however,they involve huge storage costs which makes them impractical for complex scenes724.In Global Monte Carlo Radiosity2the temporal coherence of costly visibility computations is ef?ciently and conservatively exploited,but then the radiosity solution is performed independently for each frame and all radiosity solutions are stored simultaneously in the memory.In the range-image framework30,direct and indirect lighting are independently sampled in time for selected keyframes.The temporal frequency of sampling is adaptive to the changes in scene illumination.Interpolation is performed between the obtained solutions to derive lighting for inbetween frames, but some important lighting events between keyframes can be overlooked.To avoid this problem,sparse sampling of the scene illumination can be performed for all animation frames27.However,to reconstruct lighting for a given frame Myszkowski et al.27utilize information not only from pre-ceding but also from the following frames,which are not available in the interactive scenario.
In general,it is dif?cult to adapt a typical off-line algo-rithm for interactive applications.All discussed algorithms require that the complete information on all animated scene elements is known in advance.Also,since the main goal of the off-line algorithms is to reduce the overall computation time required for rendering of the whole animation,the dif-ferences in the rendering time of particular frames are per-fectly acceptable.Thus,the constant frame rate usually can-not be kept,which is not acceptable for an interactive sce-nario.
2.2.Interactive Techniques
A number of techniques handling global illumination com-putation for dynamic environments at interactive speeds have been presented.The techniques have been designed to trade the image quality for the response speed,and their main objective is to provide a fast response for frame-to-frame changes in the environment.Early solutions41125 were embedded into the progressive radiosity framework and relied on shooting the corrective energy(possibly neg-ative)to the scene regions affected by the environment changes.
Much better performance was obtained for more re-cently introduced techniques that are based on hierarchical radiosity31833.Those algorithms introduce mechanisms for controlling the frame rate and ef?ciently identifying which part of the scene is modi?ed.However,the hierarchical ra-diosity framework poorly supports the light transfer between glossy and specular surfaces.This drawback can be elimi-nated by adding photon tracing12atop of the line-space hi-erarchy,used for diffuse surfaces8.The photons traversing changed scene regions are identi?ed using a dynamic spa-tial data structure and are selectively updated.But still,the memory requirements in all those hierarchical approaches are extremely high due to the storage of the link structure. Keller introduced the instant radiosity technique19,which, although originally proposed for ef?cient rendering of static scenes,can easily be extended to handle dynamic environ-
c The Eurographics Association2002.
ments.The technique utilizes the quasi-random walk of pho-tons based on Quasi-Monte Carlo integration.Then each photon hit point is considered as a point light source which is processed by graphics hardware.The?nal image is obtained through the view-dependent accumulation of partial images generated for each resulting light source.Keller uses the Hal-ton sequence to generate the photon hit points.A drawback here is that Keller updates the photon paths merely based on their age criterion,ignoring whether they became invalid due to the changes in the scene or not.
The algorithms proposed by Pueyo et al.31and Keller19 are view-dependent which precludes interaction involving changes of camera parameters.This de?ciency is eliminated by view-independent algorithms833,however,the whole scene illumination is always updated with equal priority, without taking into account the current camera parameters and other“importance”factors.If a complete update of the scene illumination cannot be performed during a sin-gle frame refresh cycle,then what becomes important is the order in which the progressive re?nement in various scene regions must be performed for the subsequent frames.The main goal of such an ordering of computation is to minimize the perceivable artifacts at the intermediate stages of a global illumination update,and this problem has basically not been addressed in existing solutions.In this paper we present a view-independent approach,in which the priority of update is based on the current view and the perceivability of illumi-nation artifacts.
Recently,various image caching schemes have been pro-posed,which allow for rendering of non-diffuse surfaces for changing camera positions at interactive speeds403536. Our approach could bene?t signi?cantly from such solutions which could be incorporated into our interactive global illu-mination system.In this paper we focus on global illumina-tion for diffuse environments due to the limitations of illu-mination storage in the mesh.However,during our photon tracing,arbitrary surface re?ectance functions are properly processed.
3.Overview
As a framework for global illumination computation,we chose the Density Estimation Photon Tracing(DEPT) algorithm37.The DEPT is similar to other solutions in which photons are traced from light sources towards surfaces in the scene,and the lighting energy carried by every photon is de-posited at the hit point locations on those surfaces1541.We extend the DEPT for handling dynamic environments.Also, we replace stochastic pseudo-random sequences,which are used in the DEPT to generate photon paths,by deterministic quasi-random sequences.
In our algorithm we consider the same big pool Z of pho-tons(which are traced at the initialization stage)for the whole interactive session.We update the photons computed for previous frames,which became invalid for the current frame due to interactive changes in the scene.The main problem is to identify each invalid photon in Z and to re-place it by the corresponding photon,which is traced for the current scene con?guration.Our photon tracing is based on Quasi-Monte Carlo sampling with the multi-dimensional Halton sequence.We show how the periodicity property29of this sequence,allows for immediate identi?cation of photons that have similar paths in the scene.Thus,for any invalid photon,it is easy to identify indices of all similar photons in Z that are likely to be invalid as well.Since the Halton se-quence can be used to generate any photon path based on its index,the storage costs of photon data can be eliminated. Our algorithm of photon updating is iterative.The user decides upon the iteration duration,which imposes a limit on the number of photons that can be traced per iteration. The photon update iteration consists of two stages.In the ?rst stage a subset of photons from Z are traced from the light sources to the whole environment in order to identify invalid photons.In the second stage,based on the periodic-ity property of the Halton sequences,those invalid photons are used to generate similar photons in Z,which are likely to traverse modi?ed scenes regions.Since it might be impossi-ble to update all those potentially invalid photons in a single iteration,the photon update in various scene regions is or-dered by inexpensive energy-and perception-based criteria according to the importance of outdated lighting artifacts as perceived by the user.Our algorithm is conservative in the sense that?nally,after N g iterations since the last change in the environment,all photons in Z are updated.In practice, when changes in the environment are local,a small num-ber of iterations r N g is required to remove all perceiv-able problems with the outdated illumination.The constant frame refresh rate,which is required by many practical ap-plications,is achieved by letting the user control the iteration duration and the number of such iterations per frame.
4.Quasi-Monte Carlo Sampling
The global illumination problem involves solving high di-mensional integrals.An ef?cient way to solve such integrals is to apply Monte Carlo techniques,which have an advan-tage over other integration methods because their conver-gence speed does not depend on the dimension of the in-tegral.
Monte Carlo(MC)techniques are traditionally based on pseudo-random sequences.However,it was proven that for functions with bounded variation,faster convergence can be achieved using Quasi-Monte Carlo(QMC)techniques based on quasi-random sequences17.Although integrands usually have unbounded variation in global illumination tasks,nu-merical evidence has been presented that the QMC tech-niques still have advantage over the MC techniques for real-world scenes16.
In the following section we examine basic properties of
c The Eurographics Association2002.
the Halton sequence,which is an example for the quasi-random sequence that proved to be useful in photon tracing19 and stochastic radiosity28applications.
4.1.The Halton Sequence
The Halton sequence generation is based on the radical in-
verse function,applied to an integer i.The radical inverse Φb i is the number obtained by expressing i in the base b, then reversing the order of the resulting digit sequence and
placing the?oating point at the sequence beginning13:
Φb i∑
j0a j i b j1i∑
j0
a j i
b j(1)
where a j i are subsequent digits of i.For instance Φ10123404321.
For photon shooting we need to associate the index of each photon with a sequence of numbers,thus the multi-dimensional Halton sequence must be considered.Such a se-quence is usually obtained by using prime numbers as bases for different dimensions.For example,for integer i the fol-lowing sequence can be considered:
iΦ2iΦ3iΦ5iΦ7iΦ11i(2)
When sampling discrete events,a single quasi-random number can be re-used via the remapping procedure(refer to Shirley et al.34,Fig.8).In this way we use the two?rst quasi-random numbersΦ2i andΦ3i to choose a light source and the photon emission direction,the next two num-bersΦ5i andΦ7i to determine the photon-material event (photon absorption or scattering)and the re?ection direction for the?rst photon bounce,and so on.
4.2.Periodicity of the Halton Sequence
The observation that the Halton sequence has a highly periodic nature is hardly new29.Note for example how similar the values of following base-10radical inverses are:Φ10123404321,Φ101234100004322,and Φ101234200004323.We express this periodicity property in a form which is well suited for the task of?nding similar photons(paths)in photon(path)tracing algorithms:
Φb iΦb i mN g
1
Figure1:Distribution of photons between groups for N g 4.Each row represents one group.Each group contains a number of pilot photons(rectangle)as well as a number of corrective photons(vertical lines)whose indices are spaced with interval N g.
time moment.We denote such scene properties as scene phantoms.The algorithm can consider different dynamic scene properties.The most obvious are object positions and surface BSDFs(Bidirectional Scattering Distribution Functions).
According to the periodicity property discussed in Sec-tion4.2,corrective photons are concentrated in a tight sub-space of the multi-dimensional photon space.In practice this means that corrective photons of the same group are usually emitted by the same light source,traced in similar directions, have similar probability of being absorbed when they hit a given surface,and so on.Increasing N g increases the num-ber of groups and simultaneously decreases the space span occupied by every group.Note that when changing N g it is important to keep it factorized according to Equation(5). The size and space?lling characteristics of photon groups can be tuned according to the desired properties of the global illumination update using the following parameters:
N g de?nes the photon groups number and simultaneously the span between the indices of corrective photons
N p de?nes the number of the pilot photons in each group R de?nes the ratio between the total number of photons in each group and N p.
Given those parameters,the total number of photons uti-lized by the algorithm is equal to N g N p R.All photons with indices i0N g N p are the pilot photons,and all photons with indices i N g N p N g N p R are the corrective photons.
5.2.Illumination Update
Our algorithm is fully interactive,which means that it does not require any a priori knowledge on changes in the scene. In the following discussion we assume that user interaction consists of changing object positions(the case of surface BSDF changes is easier to handle and will be
explained Figure2:The bounding volume of corrective photons from a single group starts as a pyramid,but then its shape might become more complicated as the result of photon interaction with scene objects.For the?gure clarity we marked just one bounce of photons(grey pyramids re?ected from white ob-jects)but obviously all higher bounces are also considered as required for the global illumination computation. later).Updating illumination after scene change requires that photons intersecting moving objects must be reshot. Reshooting of a photon consists of tracing it for the old scene con?guration with negative energy and then tracing it for the new scene con?guration with positive energy.Since usually only a small number of photons intersect moving objects, such double effort is justi?ed compared to calculating the solution anew.
Ef?cient searching of invalid photons is a hard problem. We attempt to solve it by subdividing the multi-dimensional photon space into relatively small volumes and searching for those volumes,which intersect the moving object.Accord-ing to the periodicity property discussed in Section4.2,the corrective photons in a single group which are emitted by a light source are bounded by a pyramid with its apex lo-cated at this light source position(Figure2).The pyramid shape might become more and more complicated as the re-sult of interaction between scene objects and the corrective photons.However,even if the pyramid is split into a number of subpyramids,the resulting bundles of photon paths still remain coherent in space and are fully bounded by those subpyramids.
The computation of intersection between bounding vol-umes of complex shape(as depicted in Figure2)and moving
objects is required to identify invalid photons.Additionally it is important to estimate the impact of those invalid photons on the correctness of rendered images.Such an estimate is required to?nd out the order in which to reshoot the photon groups,which reduces image artifacts as perceived by the human observer.We address those problems by shooting the pilot photons.
In contrast to the corrective photons,the pilot photons are not coherent and uniformly sample the space of vectors de-?ned in Equation(2).The shooting of pilot photons is in-terleaved with the shooting of corrective photons by placing them in the same group(see Figure1).Let i be the pilot photon,which intersected the moving object.We then claim that the bounding volume of corrective photons belonging to group i g with
i g i mod N g(6) intersects this object as well.Indeed,all corrective photons of that group are given by indices N g N p i g cN g,where c
is a non-negative integer.The index i given by Equation(6) differs from the index of any corrective photon of group i g by some multiple of N g.Thus,according to Equation(3),this photon is inside of the multi-dimensional pyramid,which bounds all corrective photons of that group.This means that it also is inside of the bounding volume,created when this pyramid intersects scene objects.Since the pilot photons sample the multi-dimensional vector space(de?ned in Equa-tion(2))uniformly,the number of their hits with moving ob-jects provides an approximate measure how important it is to update the group(in Section5.3we discuss in detail the corresponding problem of photon updates ordering).
Our approach to identify moving objects is not conserva-tive(refer to Briere and Poulin3and Bala et al.1for discus-sion of the conservative solutions).Even if no pilot photon detects the intersection of a group of corrective photons with a moving object,it is nevertheless possible that such an inter-section takes place.However,this typically happens if the in-tersected volume is very small and does not contribute much to the changes of global illumination.Also,when scene ob-jects stop their motion,all N g groups are?nally updated, which means that all invalid photons will be corrected,and then the only negative consequence of such undetected in-tersections is a non-optimal ordering of the group update. One may advocate that it is easy to conservatively?nd the intersection between moving objects and the?rst segment of a pyramid with the apex at the light source position(e.g., such an approach is used to reinforce the caustic photons in the photon mapping technique18),however,we are aiming for a general solution that has some potential to detect invalid photons bouncing an arbitrary number of times in the scene. Also,the density and coherence of the pilot photons in the ?rst pyramid segment is very good,which usually results in the high probability of detecting moving objects.
The pseudo-code in Algorithm1summarizes the process of illumination update.
while there are groups containing scene phantoms do
among all such photon groups,?nd the one with highest priority;
place scene phantoms of that group into BSP grid and forbid scene changes;
for all photons i in the photon group do
perform Monte Carlo tracing of photon i according
to Equation(2)without updating the global illumi-
nation;
if photon i hit dynamic object or scene phantom then
if photon i is pilot then
if photon i hit dynamic object then
increase the priority of corresponding group;
else if photon i hit scene phantom then
increase the priority of corresponding group
only if it contains intersected phantom;
end if
end if
duplicate the photon and trace two resulting pho-
tons:
-photon,which ignores scene phantoms and has
positive energy;
-photon phantom,which ignores dynamic objects
and has negative energy;
end if
end for
display partially updated solution via OpenGL;
remove all scene phantoms from the BSP grid and from just reshot photon group,allow scene changes;
set the group priority to0;
end while
nore the phantom object at position M1,and rays that ignore
the actual object at position M2.
At the moment of time t3when the object changes its posi-tion to M3,the last update of some photon groups could have
been performed at t2,but there is also a chance that some
groups have been updated only at t1.The latter groups still contain the object phantom at position M1.Since any photon
group corresponds to a frozen scene con?guration at a par-
ticular moment in the past,it cannot contain two phantoms of the same object.This is why the newly created phantom
at position M2must be placed only in those photon groups,
which do not contain the phantom at position M1.
User interaction with surface BSDFs is processed in a similar way as described in Algorithm1.However,this does
not involve any update of the ray tracing acceleration data
structures.The scene phantoms store the surface BSDFs from the last iteration in which photons from the current
group were updated.
In our current implementation user interaction with light sources is not supported,although it is relatively easy to ex-
tend our algorithm for this purpose.A number of special
cases for changing the light source position,emitted energy, goniometric diagram and so on should be considered.For ex-
ample,user interaction changing the position of light sources
should result in increasing the update priority for all groups
for which photons are emitted by dislocated light sources. The old position of the light source should be stored as the
scene phantom.
5.3.Priority of Photon Groups Processing
An important issue is setting priorities of photon group pro-cessing in order to minimize the perceivability of illumina-
tion artifacts by the user.For this purpose we consider three
factors which affect the image appearance:
Changes in the scene detected by the pilot photons. Visual masking of lighting patterns by textures.
Current camera view frustum.
The pilot photons are used to compute the importance of
photon groups.If pilot photon i hits a dynamic object,the
importance P of the group i g is increased by increment?p. Also,if a scene phantom is hit by i and belongs to the list
of phantoms for i g,P is increased by the same increment
?p(some arbitrary value is chosen,e.g,?p1).The im-portance increment?p can be reduced for a given photon
hitting a texture as the result of visual masking.
Visual masking of lighting patterns by textures may sig-ni?cantly reduce the observer sensitivity to artifacts in the scene illumination.For surfaces with strong masking,the priority of illumination update can be reduced with respect to non-textured surfaces.We follow the approach by Du-mont et al.10in which the VDP proposed by Ramasub-ramanian et al.32is used to estimate the visibility thresh-old elevation T e for textures at the preprocessing stage.
We
a)b)
Figure3:Visual masking processing a)sample texture and
b)visibility threshold elevation map(brighter regions in the
map correspond to higher masking).
introduce one modi?cation to this procedure which is in-
spired by Luebke et al.23.For a given mesh density and texture mapping parameters for this mesh it is possible to
estimate the relation between the highest spatial frequency
of indirect illumination reconstructed using this mesh and the spatial frequencies in the texture.The visual masking
can be observed mostly between stimuli of similar spatial
frequencies6.Therefore,prior to the VDP processing we eliminate from the texture all frequencies higher than the
mesh imposed maximum frequency of indirect illumination.
This modi?cation makes our approach more conservative and excessive values of T e can be avoided.As a result of the
VDP processing we obtain a set of the average T e values for
a given texture at each MipMap level.In Figure3(see Ap-pendix/Color section)we show an example of the visibility
threshold elevation map obtained using our VDP.
During photon tracing we access textures assigned to
scene surfaces in order to estimate the probability of photon
absorption and to determine the color of scattered photons. While the texture is sampled at its original resolution,we
need to access T e at the proper MipMap level.For this pur-
pose we use a simple heuristic which takes into account the surface distance to the observer and its spatial orientation.
We use the T e value for the photon hit texture to modify the
importance P of the group i g by increment?p T e.This is an application example in which the perception-based error
metric is used to steer the global illumination computation
with negligible overhead costs.Also,the potential inaccura-cies of such perceptual steering are fully recoverable in our algorithm because only the computation ordering is affected. Although our algorithm is view-independent,better ef?-ciency of illumination update can be achieved by assigning higher priorities to the visible regions of the scene.We ef?-ciently combine visibility information with the group impor-tance P by controlling the visibility status V for every photon group.This visibility status is updated for every frame as a by-product of the pilot photons tracing.It is costly to deter-
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mine the visibility of the photon hit exactly,thus we only use view frustum culling here.Photon hits inside of view frus-tum can affect the image quality,so we increase V of the corresponding group.In contrast to the value P,V is view dependent and we have to reset it after each camera change. Thus,V is taken into account only if the number of pilot pho-tons,shot after the last camera change,is suf?cient for its robust estimate.Otherwise,we assume that V1for each group.
After the pilot photons of the current group are shot,and V and P are updated,the next group of corrective photons with the highest priority measured as V P is selected.
6.Implementation
We implemented our algorithm as a hybrid rendering sys-tem where graphics hardware is responsible for computing direct illumination,the corresponding hard shadows,and vi-sualizing the indirect illumination.The software part of our engine is mostly dedicated to calculating the indirect illumi-nation.Both parts run in parallel using multi-threading,and are synchronized by the important events(update of indirect illumination,user interaction etc.).
For scenes with multiple light sources,whose processing would require many rendering passes of graphics hardware, another strategy of direct lighting computation can be con-sidered.The user may select the most important for his ap-plication light sources to be processed by graphics hardware to obtain the good quality of shadows.The remaining light sources can be processed on the photon basis without any extra cost since photons are traced from the light sources anyway.The problem with such an approach is that the di-rect illumination is then reconstructed on the mesh basis and the resulting shadow boundaries are fuzzy with some possi-ble artifacts.
Shooting photons requires ef?cient ray tracing accelera-tion data structures for dynamic environments.Initially we relied on multi-level voxel grids.Recently,we switched to the axis-aligned BSP-tree with a cost function14,which allowed us to improve the computation performance sig-ni?cantly(up to3times).At present we do not use any hardware-dependent optimizations of ray tracing(e.g., SIMD,prefetching,and so on)as suggested by Wald et al.39. Obviously by adding such optimizations the ray tracing per-formance could be further improved.
6.1.Direct Illumination
For computing the effect of direct illumination we chose to use OpenGL-compliant graphics hardware.Instead of re-stricting ourselves to the?xed function pipeline of standard OpenGL we utilize programmable vertex and pixel hardware to gain the highest qualitative and most ef?cient rendering possible.Our current implementation is customized to run on NVIDIA GeForce3graphics cards,but can of course also be implemented on any other card with similar features(e.g. ATI’s Radeon series).
6.1.1.Shadows
One of the main aspects of image quality is an accurate rep-resentation of shadows.Although shadow mapping42is di-rectly supported by the graphics hardware it is problematic due to its sampling problems.Another disadvantage is that for dynamic environments shadow maps change very often which would lead to a huge amount of regeneration passes. We therefore prefer the shadow volume algorithm proposed by Crow5since it
generates very precise shadows by performing calcula-tions in object space,
can be ef?ciently implemented using graphics hardware, and
is appropriate for dynamic environments.
For complex scenes the generation of shadow volumes, which requires?nding the silhouette edges of all objects with respect to the light source,is quite expensive.By ex-ploiting temporal coherency of shadow volumes we can limit the regeneration of shadow volumes to those objects that are moving and reuse the volumes of all static objects from the previous frame.
Our shadow volume implementation is based on the hard-ware stencil buffer scheme presented21,which solves the problematic cases of shadow volumes intersecting the near clipping plane.
With normal OpenGL the shadow volume algorithm would require N1rendering passes where N is the num-ber of shadow casting light sources.However using pro-grammable features available on recent graphics hardware20 we are able to collapse up to4passes into a single one.This is done by?rst rendering the scene’s geometry as seen by the camera,resulting in having the depth values of the front most pixels in the depth buffer.After this we loop over the ?rst four light sources where in each step we?rst initialize the stencil buffer and draw shadow volumes with the corre-sponding stencil operation(increment/decrement).The con-tent of the stencil buffer,which corresponds to the shadow test result,is then copied to one of the color buffer channels (red channel for?rst light,green channel for second,etc.) and the stencil buffer is initialized for the next light source. After this loop we obtain a RGBA shadow mask containing the shadow information for up to four light sources.
In the?nal rendering pass we then render the scene once again but this time using a customized vertex program22 which instead of summing up all lighting contributions for a given vertex uses additional output attributes that hands out the illumination for light source L03separately.These values will then be linearly interpolated over the primitive (triangle)and passed to the texture blending stage.
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Having the shadow mask as an projective RGBA texture we can apply the shadow result separately for each of the four light sources and output the total illumination as the pixel value.
out indirect illum L0mask R illum L1mask G
(7) For more light sources this approach can be extended by sim-ple multi-pass rendering.So for N light sources we have to generate N4shadow masks.Another N4passes are needed to compute the illumination.These passes can then be summed up using additive blending or the accumulation buffer.
This shadow mask scheme is not only very ef?cient but also enhances image https://www.wendangku.net/doc/0b6360537.html,ing the normal loop scheme, the contributions of all light sources need to be summed up using either the accumulation buffer or additive blending. Since both operations are performed at the end of the pixel pipeline precision is limited to(normally)8bits per color channel,whereas our approach sums up at an earlier stage in the pipeline where precision is much higher.Accuracy is also increased for N4since we use the accumulation buffer(or additive blending)for groups of four light sources rather than summing up the contribution of individual lights. Another advantage is that our method does not suffer from z-?ghting artifacts which normally occur when rendering the scene several times.
6.1.2.Goniometric Diagrams
In order to achieve realistic image quality we also choose to support complex point light sources with non-uniform di-rectional power distribution.Description of these goniomet-ric diagrams are available in standardized formats and are essential for accurate lighting computations.
We include these distributions by re-sampling from the standard format to a cube map texture38,which can ef?-ciently store the complete360o view of a point light source and which is supported by the graphics hardware. Restricting ourselves to monochromatic goniometric dia-grams we can include these as an additional scaling factor for the local illumination of a given light source.Referring to Equation7the mask scaling factor,which was considered to be either1.0for lit and0.0for shadowed pixels,can be used to perform this additional scaling.In the?rst rendering pass we render using the appropriate cube map textures and store the scaling factors in one of the color https://www.wendangku.net/doc/0b6360537.html,ing four texture units and RGBA masking we are able to gener-ate these for4light sources simultaneously.When copying the result of the shadow test back to the color buffer we set all pixels to00where the shadow test succeeded.Although the dynamic range of these textures is limited to00to10 this method still improves image quality signi?cantly while introducing only a minimal overhead.7.Results
We present results that we obtained for the ROOM scene (about12,400mesh elements)and for the HOUSE scene (about377,900mesh elements).The ROOM scene is illumi-nated by four,the HOUSE scene by two light sources with goniometric diagrams.Figures4(see Appendix/Color sec-tion)show snapshots of the two scenes obtained during an interactive session.
All timings were measured on1.7GHz Dual P4Xeon computer with an NVIDIA GeForce364MB videocard.The frame rate is governed by the speed of OpenGL rendering. For the ROOM scene8fps and for the HOUSE scene1.1fps are achieved,which includes the display of indirect lighting, and direct lighting with shadow computations performed by the graphics hardware.Our current implementation does not support triangle strip generation which affects the refresh rate.This however is not a limiting factor for the perfor-mance of indirect lighting update because it is re?ned at an even slower pace.
As we mentioned in Section5.1,our algorithm perfor-mance can be tuned by the parameters N g,N p and R.The parameter N g controls the number of the Halton sequence dimensions,for which corrective photons of the same group remain coherent.We chose the initial factorization of N g for two dimensions to be2332.This splits the?rst and second di-mensions to8and9spans,respectively.The remapping pro-cedure(refer to Section4.1),applied after the light source selection step,effectively reduces the spatial coherence in the?rst dimension.To compensate for this,we increase the corresponding power k2proportionally to the number of light sources present in the scene.This results in factoriza-tions2532and2432for the ROOM and HOUSE scenes,re-spectively.
The graphs in Figure5demonstrate the in?uence of N g parameter on the speed of the global illumination update as the result of an object movement from one position to an-other.The ef?ciency of the update is measured by the num-ber of reshot relevant photons as a function of time.We call those photons relevant,whose hit points are dislocated as a result of scene changes.All relevant photons must be reshot to complete the illumination update.The algorithm perfor-mance is compared for N g288(factorization:2532)and N g10080(factorization:25325171).For N g288only direct photons belonging to a group are spatially coherent, while for N g10080also the?rst bounce of scattered pho-
tons is coherent.Two cases are considered for each of the N g values:the moving object is illuminated1)directly and2) indirectly.In the?rst case the number of groups has a small impact on the performance of illumination update.This can be explained by the fact that the moving object is mostly hit by the direct photons,which are coherent even for small N g. If the moving object is illuminated indirectly,a much better performance is obtained for larger N g because the coherence
c The Eurographics Association2002.
a)b)
Figure5:The number of found relevant photons as a function of time.The moving object is illuminated by a)both direct and indirect lighting,b)only indirect lighting.The horizontal line shows the total number of relevant photons,which must be updated.
of the?rst bounce of re?ected photons becomes important.
Such coherence is not ensured for N g288.
Figure6(see Appendix/Color section)shows the ability
of the algorithm to?nd the coherent photons after the?rst in-direct bounce from the surface.Photons from both depicted
groups re?ect diffusely from the?oor in the direction of the
moving objects.
The speed of the global illumination update depends
strongly on the pilot photon’s ratio in the pool,which de-?nes the precision of the group priority computation.If this
ratio is too small,important photon groups can be missed
and then reshot too late.Conversely,if the number of pilot photons is too large,the update ef?ciency is reduced because
the pilot photons are shot essentially in a random order.Fig-
ure7demonstrates this dependency for the ROOM scene.N p and R values are selected in such a way,that the total num-
ber of photons is constant and only the ratio of pilot photons
changes.We have found that R16,which corresponds to only6.25%of pilot photons in the pool,yields nearly op-
timal performance.As can be clearly seen in Figure7,for
R32(3.125%of pilot photons)the photon group ordering is not robust and the overall update performance is worse. According to our experiments,full recovery of perceiv-able illumination artifacts resulting from the furniture move-ments in the ROOM and HOUSE scenes usually takes2–4and 4–8seconds,respectively.The total number of photons in the pool for the ROOM scene was1,152,000and for the HOUSE scene1,728,000.
Storing the photon paths for all photons could be man-
ageable for the number of photons we presently use,which
could perhaps help to avoid some computation,e.g.,tracing some photons with negative energy.However,our experi-ments have shown that tracing changed photon paths twice introduces an overhead which on average was below25% (some initial segments of the photon path may be the same
Figure7:Number of found relevant photons as a function of time,depending on the ratio R between the total number of photons and the number of pilot photons.The total number of photons in the pool is constant.The dotted line shows the theoretical update progress under the assumption that the photons are updated in a random order.
and can be computed only once).Handling stored photon paths would incur some overhead,and the extension of our algorithm to handle more photons and a?ner mesh in or-der to obtain an even better quality of lighting reconstruc-tion would be more dif?cult(e.g.more than one proces-sor for photon tracing could be used or a faster ray tracing algorithm39could be implemented).
8.Conclusions
We propose a novel interactive global illumination technique for dynamic environments which is suitable for processing complex scenes.Based on the periodicity property of the Halton sequence we are able to trace photons coherently only into those scene regions which require the illumination
c The Eurographics Association2002.
https://www.wendangku.net/doc/0b6360537.html,ing our technique,the temporal coherence of the scene illumination can ef?ciently be exploited without any signi?cant storage of data involving the temporal domain. Progressive re?nement of rendered frames is steered using energy-and perception-based criteria in order to minimize image artifacts as perceived by the user.As a result subse-quent frames can be ef?ciently rendered and the temporal aliasing is practically reduced below the perceivability level. The quality of the direct lighting distribution and shadows signi?cantly bene?t from our ef?cient hardware implemen-tation.
Selective photon tracing has many potential applications which require local reinforcement of computations based on some importance criteria.An example of such an applica-tion is the ef?cient rendering of high quality caustics,which usually requires a huge number of photons.After identify-ing some paths of caustic photons,more coherent caustic photons can easily be generated using our approach.The drawback of many existing photon based methods is that too many photons are sent into well illuminated scene regions with a simple illumination distribution,and too few photons reach remote scene regions.This de?ciency could easily be corrected using our approach,by skipping the tracing of re-dundant photons and properly scaling the energy of the ac-tually traced photons.As future work we plan to pursue our research along those avenues.Also,we would like to include specular and glossy effects into our interactive renderer us-ing pixel-selective ray tracing.
9.Acknowledgments
We would like to thank Philippe Bekaert,Katja Daubert and Vlastiml Havran for their helpful comments and sug-gestions.This work was supported in part by the European Community within the scope of the RealRe?ect project IST-2001-34744“Realtime visualization of complex re?ectance behavior in virtual prototyping”.
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a)b)
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.
a)b)
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实业有限公司简介
公司简介怎么写 一， 首先介绍一下你们公司的名字，什么性质的，什么时间成立的，有多少员工，主要产品是什么及它的应用范围，自成立以来取得什么样的成绩（包括销售方面、技术创新方面、人员培训方面等等），在未来几年内的发展规划等等。注意千万不要写成泛文，要写得有理有据，还要突出重点，具有很强的吸引力。 二， 1，公司背景 如何成立，建立人，公司的历史，内容发展 2，公司服务内容或者产品介绍 3，公司员工和公司的结构介绍 4，公司的顾客群或者范围介绍 5，公司近期内的重大发展介绍 6，公司的年度报表简介 不过最重要的，建议你弄明白看这个公司简介的对象是谁，知己知彼才能百战百胜。不知道对象是谁就提笔写东西，是很不明智的。我给你的是比较常用的方式，不适用于所有对象群体。 三， 1.要体现出你的公司的独特个性。 2.不能学习别人的，才会有自己的个性。 上海富蔗化工有限公司座落于中国经济、金融、贸易中心--上海。公司位于上海西北部-上海桃浦化工工业园区。是集化学科研，开发，生产，销售，服务为一体
的综合型企业。本公司在奉贤，南汇，松江等工业园区及江浙一带均有生产和联营企业基地。我公司拥有先进的生产设备，完善的产品检测手段和质量保证体系。我公司的员工具有较强的责任感。经过多年的发展，现已形成有机中间体、医药中间体、化工溶剂和化工助剂四大类上百个品种。公司业务涉及医药、农药、染料、涂料、制革等各行业。公司年销售额在数千万人民币左右。我公司与世界各大化工、医药原料供应厂商有着密切的联系，并与其保持着良好的合作关系，能够稳定、成立以来，发挥自身优势，健全销售网络，注重企业形象，开创了上海首家在网络上以小包装零售业带动大批发销售的多元化经营模式，并且不断增加原料品种的配套措施，赢得广大客户的一致好评。企业产品市场辽阔，远销日本、美国、欧洲、印度，东南亚等地。我们富蔗人本着“求实、高效、创新”的团队精神，参与到激烈的市场竞争中来，以一流的产品质量，优惠的产品价格，令人满意的销售服务，赢得您的支持与信赖。我们愿同四海知音、各界同仁携手共同发展。企业使命： ----立足化工行业，开拓进取。诚信服务，以质量和信用为本。规范管理，引进先进、科学方法。加强合作，建立良好关系。开发新品，发展实业，优化产业结构。创立品牌，报效国家，为经济发展、环境保护和社会进步做出贡献。富蔗承诺，为您负责。 [正派] 经营是富蔗的一贯原则[创新] 进取是富蔗的生存基础 [团队] 协作是富蔗的致胜法宝 深圳市国冶星光电子有限公司是目前国内少数大型综合性LED光电产品生产性高科技企业之一，公司集科研、开发、生产、销售、服务为一体，专业生产发光二极管、数码、点阵、（室内、室外、半户外）模块、背光源、贴片（SMD）LED等全系列光电产品，产量大、品质高，产品广泛应用于家电、手机、公共场所、交通、广告、银行等，为大型家电、手机厂的配套供应商。 公司拥有先进的专业生产设备、世界领先的全自动SMD生产线及一系列品质保证测试设备（自动固晶机、自动焊线机、模造机、自动切割机、自动分光机、自动装带机、冷热冲击机、可程式恒温恒湿机、定点型恒温恒湿机、环境测试机、电脑分析显微镜等），拥有高素质的管理队伍，高水平的技术、开发人员及一大批训练有素的熟练工人。生产原材料均采用当今国外知名企业产品，现有市场已覆盖全国各地，海外业务拓展已具规模，
土耳其电力市场分析
土耳其电力市场土耳其电力市场概况概况 一一、土耳其电力市场发展现状土耳其电力市场发展现状 随着土耳其经济的高速发展，土耳其电力市场正成为土耳其经济发展最快的领域之一。自1980年起，土耳其的电力需求就开始快速增长，2009年达到了194兆瓦特-小时（TWh）（图1）。目前土耳其的人均用电量低于2200千瓦时，远低于欧盟6602千瓦时的平均水平。根据土耳其能源部最近的调查显示，土耳其的电力需求将从2008年的198 TWh 增加到2017年的363TWh。 图1 19801 1980--2009年土耳其电力需求年土耳其电力需求（（TWh TWh）） 数据来源：TEDA ?，E üA ?。 注：7.8%、3.6%是复合年均增长率（CAGR）。 电力产业可分为四个垂直分工的部门：发电、传输、分配和零售。在土耳其，目前除了传输环节仍完全由国有公司TEIA ?控制外，其他环节均引入了私营企业（图2）。
数据来源：EüA?，TE?A?，TEDA?。 土耳其电力市场自由化时间表 二、土耳其电力市场自由化时间表 在土耳其电力工业的发展初期，曾有外国企业参与，之后由地方公共团体承担。1950年以后，私营企业逐渐参与。1970年10月，根据国家第1312号法令，设立土耳其电力局(TEK)，垄断性的经营发电、输电、配电业务。根据土耳其3096号法令，从1984年开始，允许私营部门进入电力市场，但只有极少数的民营企业参与经营电力。1994 年，一贯垄断经营发电、输电、配电的TEK被分割成发电、输电公司TEA?和配电公司TEDA?。2001年 TEA?解体为EüA?、TE?A?和TEDA?，这三家公司的主营业务分别是发电、输电和零售。2005-2010年，土耳其配电领域的私有化开始，预计在2005-2010的5年中TEDA?将被21个私营配电公司所取代。2007年，土耳其发电领域开始了私有化进程。2008年，拥有总装机容量141MW的ADüA?公司成功完成了私有化，这是土耳其政府私有化管理局（Privatisation Administration）
unit4globalwarming单词和句型重点总结
Unit 4 Global warming全球变暖 一、词汇 about发生；造成 注意：（1）come about是不及物动词短语，不能用于被动语态，常指情况不受人控制的突然发生。有时用it作形式主语，that从句作真正主语。 （2）表示“发生”的词或短语有：happen,occur,take place,break ① Many a quarrel comes about through a misunderstanding. ② The moon came out from behind the clouds. ③ I’ll let you know if anything comes up. ④ I’ll come over and see how you are coming along. ⑤ I came across an old friend yesterday. ⑥ When she came to, she couldn’t recognize the surroundings. ① I subscribe to your suggestion. ② Which magazine do you subscribe to? ③ He subscribed his name to the paper（文件）. ④ He subscribed a large sum to the poor students. n.量；数量
① It’s cheaper to buy goods in quantity / in large quantities. ② A large quantity of silk is sold in Japan. ③ A large quantity of drugs are found in his home. ④ Large quantities of rain are needed in this area. ① He tends to get angry when others disagree with her. ② His views tend towards the extreme（极端）. ③ He was tending (to) his son when I saw him in the hospital. ④ Jane is nice but has a tendency to talk too much. =Jane is nice but she tends to talk too much. ① The price of the new house in our area has gone up by 1,000 yuan per square meter（平方米）。That is（也就是说）it has gone up to 5,000 yuan per square meter. ② The wind has gone down a little. ④ The country has gone through too many wars.
个人公司章程
个人公司章程 公司章程 一、总则 第一条依据《中华人民共和国公司法》、《中华人民共和国公司登记管理条例》及有关法律、法规的规定，制定本公司章程。本公司章程对公司股东、董事、监事、经理均具有约束力。 第二条公司经公司登记机关核准登记并领取法人营业执照后即告成立。 二、公司名称和住所 第三条公司名称：有限公司。(以预先核准登记的名称为准) 第四条公司住所：市(县镇)路(街)号。 三、公司的经营范围 第五条公司的经营范围：(含经营方式)。 四、公司注册资本 第六条公司的注册资本为全体股东实缴的出资总额，人民币万元。(要符合法定的注册资本的最低限额) 第七条公司注册资本的增加或减少必须经股东会代表2/3以上表决权股东一致通过，增加或减少的比例、幅度必须符合国家有关法律、法规的规定，而且不应影响公司的存在。 五、公司股东名称
第八条凡持有本公司出具的认缴出资证明的为本公司股东，股东是法人的，由该法人的法定代表人或法人的代理人代表法人行使股东权利。 第九条公司在册股东共人，全部是法人股东 股东名录： (一)法人股东： 1.法人名称： 住所： 法定代表人： 认缴出资额：万元，占公司注册资本的 % 出资方式： (货币或实物或其它) 认缴时间：年月日 2.…………………………………… 第十条公司置备股东名册，并记载下列事项： (一)股东的姓名或者名称及住所; (二)股东的出资额; (三)出资证明书编号。 六、股东的权利和义务 第十一条公司股东享有以下权利： 1.出席股东会，按出资比例行使表决权;
2.按出资比例分取公司红利; 3.有权查询公司章程、股东会会议记录、财务会计报表; 4.公司新增资本时，可优先认缴出资; 5.按规定转让出资; 6.其它股东转让出资，在同等条件下，有优先购买权; 7.有权在公司解散清算时按出资比例分配剩余财产; 第十二条公司股东承担以下义务： 1.遵守公司章程; 2.按期缴足认购的出资; 3.以其出资额为限对公司承担责任; 4.出资额只能按规定转让，不得退资; 5.有责任保护公司的合法权益，不得参与危害公司利益的活动; 6.在公司登记后，不得抽回出资; 7.在公司成立后，发现作为出资的实物、工业产权、非专利技术、土地使用权的实际价额显著低于公司章程所定价额的，应当由交付该出资的股东补交其差额，公司设立时的其他股东对其承担连带责任 七、股东(出资人)的出资方式和出资额 第十三条出资人以货币认缴出资额。(以实物、工业产权、
中东国家有哪些风俗
中东包括那些国家？ “中东地区”或“中东”是指地中海东部与南部区域，从地中海东部到波斯湾的大片地区，“中东”地理上也是非洲东北部与欧亚大陆西南部的地区。 中东名称的来源据说是：16－17世纪欧洲殖民者向东殖民时，把距离欧洲的地理位置按远近划分成了：近东，中东，远东。 中东大部分为西亚，但与西亚的区别是：1.中东不包括阿富汗。2.中东包括非洲国家埃及。3.中东包括了土耳其的欧洲部分。 中东是两洋三洲五海之地，其处在联系亚欧非三大洲，沟通大西洋和印度洋的枢纽地位。其三洲具体指亚欧非三大洲，五海具体指里海，黑海，地中海，红海，阿拉伯海。交通便利，海陆空的路线，可顺利运送石油到各国。 “中东”不属于正式的地理术语。一般说来包括巴林、埃及、伊朗、伊拉克(专题，图库)、以色列、约旦、科威特、黎巴嫩、阿曼、卡塔尔、沙特、叙利亚、阿联酋和也门，巴勒斯坦、马格里布国家(阿尔及利亚、利比亚、摩洛哥、突尼斯)以及苏丹、毛里塔尼亚和索马里，由于其历史文化原因一般认为属于中东国家，土耳其和塞浦路斯尽管地理上属于中东地区的一部分，但是他们自身认为属于欧洲；北边的阿富汗有时也与中东联系密切。 政治概念上的中东问题系指阿拉伯国家（包括巴勒斯坦）与以色列之间的冲突问题，也称阿以冲突。中东问题是列强争夺的历史产物，也是世界上持续时间最长的地区热点问题，至今已半个多世纪。中东问题的核心是巴勒斯坦问题。 中东包括那些国家？使用的语言？ “中东”概念究竟包括哪些国家和地区，国内外尚无定论，但一般泛指西亚，北非地区，约24个国家，1500余万平方公里，3.6亿人口。 西亚国家包括沙特、伊朗、科威特、伊拉克、阿联酋、阿曼、卡塔尔、巴林、土耳其、以色列、巴勒斯坦、叙利亚、黎巴嫩、约旦、也门和塞浦路斯。 北非包括：苏丹、埃及、利比亚、突尼斯、阿尔及利亚、摩洛哥、马德拉群岛、亚速尔群岛 阿拉伯国家主要用阿拉伯语、库尔德语、土耳其语、波斯语，以色列主要用希伯来语. 中东包括北非的埃及和西亚各国中除了阿富汗以外的其他国家。主要使用阿拉伯语。 中东地区都有什么语言?各自国家的母语都是什么? 中东地区国家包括巴林、埃及、伊朗、伊拉克、以色列、约旦、科威特、黎巴嫩、阿曼、卡塔尔、沙特、叙利亚、阿联酋和也门，巴勒斯坦、马格里布国家（阿尔及利亚、利比亚、摩洛哥、突尼斯）以及苏丹、毛里塔尼亚和索马里,这里面大多数阿拉伯国家的通用语言是阿拉伯语,以色列的通用语言是希伯来语,伊朗的通用语言是波斯语,土耳其和塞浦路斯虽然地理上属于中东地区,但他们一般认为属于欧洲，而阿富汗虽地理上不属中东地区，但与中东联系密切.此外,在这些国家还有大量的民族,比如说库尔德族、贝督因各部族，这些民族说本民族的语言。而苏丹等东非洲国家通用英语. 因信奉伊斯兰教，通用官方语言是阿拉伯语，只是类似于我国的方言，发音有区别，以色列说的是希伯来语，伊朗说的是波斯语，土耳其说土耳其语. 中东国家有哪些风俗? 阿联酋虽然是穆斯林国家，信仰伊斯兰教，但国家实行对外全方位开放，政策较开明，对外国人在衣食住行等方面没有太多的限制，超级市场可以买到猪肉及其制品，基本可满足居住在阿联酋各国人士的需求，值得注意的是：
深圳市大诠实业有限公司简介及产品介绍
深圳市大诠实业有限公司简介 深圳市大诠实业有限公司大诠旗下网络变压器厂于2007年6月成立，公司主要生产脉冲变压器、滤波器、磁环线圈等磁性元件。2016年注册属于大诠实业的自主网络滤波器品牌NMS.工厂面积5000多平方米，前期项目总投资三百多万元人民币，目前年产值达6000多万元人民币。 公司属于内资企业，总部设于深圳市龙华新区大浪街道，现有员工300人左右。其中一些工厂在云南文山市环城西路中部，下辖13个分厂约7000人。大诠实业东莞工厂位于广东省东莞市高埗镇芦溪村银涌工业区创鸿基工业园四楼。公司目前正处于高速发展时期，是同行客户信得过的企业。 大诠优势 所有产品均符合全球业界各项质量及环保规定。公司拥有一个经验丰富的管理团队，有一批爱岗敬业，开拓进取，团结一心，坦诚从事之优秀员工，有公正严明的规章制度及相对完善的管控体系。 公司经过多年的锤炼，积累了丰富的集生产加工，开发，品质，后勤保障等各种管控经验，有多渠道固定之客户群，客户遍布珠三角，长三角以及欧美，东南亚等发达国家和地区。也有永久持续，品质交期稳定之产品前段供应链。 大诠文化 愿景：成为全球网络变压器最具领导地位的生产商！ 使命：为网络通讯行业提供最具竞争力的多元化网络变压器！ 理念：与员工共成长，与客户求共赢！以质量创品牌，以诚信谋发展！ 精神：开拓、创新，立足市场求发展；优质、高效，专心服务为用户! 价值观：以人为本，客户至上，诚信经营，大家共赢！ 工作作风：产前准备严格核对；生产过程严格要求； 员工作业严格规范；出厂成品严格把关。 服务宗旨：每位客户的满意是环宇人存在价值的最好体现！ 大诠产能（300K/天） 12PIN（超薄）SMD 20K/天 16PIN （常规）SMD 50K/天 24PIN（小）SMD 60K/天 24PIN（大）SMD 20K/天 48PIN（常规）SMD 10K/天 18PIN（单排常规）DIP 5K/天 36PIN（单排常规）DIP 10K/天 24PIN（双排常规）DIP 10K/天 48PIN（双排常规）DIP 15K/天 设备仪器列表 序号设备名称数量用途序号设备名称数量用途 1 TCP 1 集高压测试、综合测试、外 观检验、包装于一体的设 备。 14 切脚机 6 DIP产品切脚设备 2 射频网络分 析仪 1 产品特性测试15 显微镜8 产品局部放大，用于分析产品异 常。
中东一带一路国家、土耳其市场分析
二、中线 路线走向：中国（北京、郑州、西安、乌鲁木齐）——中亚——西亚及中东——中欧——西欧 中亚 一句话概况：（机遇）中亚地区电商起步晚，发展相对落后，算是一块未开垦的处女地。 从相关资料了解到，目前，(优势)中亚大部分国家（包括哈萨克斯坦、乌兹别克斯坦、土库曼斯坦、吉尔吉斯斯坦、塔吉克斯坦和阿富汗斯坦）已经有宽带接入，网络基础设施建设有助于互联网用户的增长，但（劣势）中亚地区互联网的商业用途还远远低于亚洲其他国家。同时，由于物产相对匮乏，中亚地区居民生活所需品严重依赖进口，跨境电商是其目前主要的电商形式。 根据市场调研来看，2015年中亚地区的跨境电商已有了重大改变，这主要得益于哈萨克斯坦进入了WTO提高了商业透明度、吉尔吉斯斯坦对欧盟消费进一步扩展等。而促进中亚地区电子商务迅速发展的原因主要有两点： 1、电子商务可以有效降低商品价差，同时由于信息不透明和贸易水平落后，市场上存在严重的价差，而中亚也成为了世界上货物最贵的地方。但是电子商务的发展和渗透可以有效地解决这一问题。 2、电子商务能够触及到传统进口市场无法满足的人群，包括女性（中亚地区居民多为穆斯林，女性有许多禁忌）、小企业和乡村企业。 据悉，哈萨克斯坦的B2C网站chocolife.me和吉尔吉斯斯坦B2B网
站prodsklad.kg比较活跃，也在一定程度上刺激了中亚电商的发展。另外，由于（威胁）在中亚地区，信用卡使用限制，网络支付存在很大风险，货到付款是目前主要的支付方式。 西亚及中东 一句话概况：中东市场有两个鲜明的形象：（机会）一是易被忽视的“金矿”，二是跨境电商伺机爆发。 从告了解到，中东地区电商市场从2011年的70亿美元增长至2012年的90亿美元，有29%的涨幅，2013年这一规模达到112亿美元，2014年达到128亿美元，2015年突破150亿美元。 中东地区各国电商渗透率为：阿联酋46%，沙特阿拉伯25%，黎巴嫩9%，埃及8%，科威特35%。根据Research and Markets的报告，从B2C电商销售额来看，阿联酋是中东地区最大的B2C电商市场，沙特阿拉伯是中东地区第二大B2C电商市场。 在电商基础设施上，物流方面，中东地区的公司只能通过公路传送货物而不是飞机，且目前没有公认的法律规定可参考。支付方面，大约80%的网上购物是货到付款，15%是信用卡和借记卡支付。 由于联系亚、欧、非三大洲，沟通大西洋、印度洋，中东地区自古以来就凭借十分重要的地理位置成为国际贸易要塞。这一地区给人的总体感觉是，居民有钱（石油输出国），但物资缺乏，所以人们跨境网购的热情非常高。 在这一背景下，Amazon、eBay等全球电商早早的就进入中东市场，而近年来，中国的电商企业在此也颇为活跃。根据中国跨境出口电商商
高中英语《Unit4Globalwarming》课文语法填空新人教版
《Unit 4 Global warming》 Does It Matter? 一、语法填空(根据课文内容、依据语法规则完成下面短文） When 1________ (compare) with most natural changes, that the temperature of the earth rose about one degree Fahrenheit during the 20th century is quite shocking. And it’s human activity 2________ has caused this global warming rather 3________ a random but natural phenomenon. Dr. Janice Foster explains that we add huge 4________ of extra carbon dioxide into the atmosphere by burning fossil 5________. From the second 6________ and the discovery of Charles Keeling, all scientists believe that the burning of more and more fossil fuels 7________ (result) in the increase in carbon dioxide. Greenhouse gases continue to build up. On the one hand, Dr. Foster thinks that the trend would be a 8________. On the other hand, George Hambley 9________ (state) that more carbon dioxide would encourage a greater range of animals and bring us 10________ better life.
个人开公司必备知识
个人开公司必备：注册、税务 一、选择公司的形式：- 普通的有限责任公司，最低注册资金3万元，需要2个（或以上）股东，从06年1月起新的公司法规定，允许1个股东注册有限责任公司，这种特殊的有限责任公司又称“一人有限公司”（但公司名称中不会有“一人”字样，执照上会注明“自然人独资”），最低注册资金10万元。-- 如果你和朋友、家人合伙投资创业，可选择普通的有限公司，最低注册资金3万元；如果只有你一个人作为股东，则选择一人有限公司，最低注册资金10万元。- 二、注册公司的步骤：- 1.核名：到工商局去领取一张“企业（字号）名称预先核准申请表”，填写你准备取的公司名称，由工商局上网（工商局内部网）检索是否有重名，如果没有重名，就可以使用这个名称，就会核发一张“企业（字号）名称预先核准通知书”。这一步的手续费是30元。（30元可以帮你检索5个名字，很多名字重复，所以一般常见的名字就不用试了，免得花冤枉钱） 2.租房：去专门的写字楼租一间办公室，如果你自己有厂房或者办公室也可以，有的地方不允许在居民楼里办公。租房后要签订租房合同，并让房东提供房产证的复印件。- 签订好租房合同后，还要到税务局去买印花税，按年租金的千分之一的税率购买，例如你的每年房租是1万元，那就要买10元钱的印花税，贴在房租合同的首页，后面凡是需要用到房租合同的地方，都需要是贴了印花税的合同复印件。-- 3.编写“公司章程”：可以在工商局网站下载“公司章程”的样本，修改一下就可以了。章程的最后由所有股东签名。- 4.刻私章：去街上刻章的地方刻一个私章，给他们讲刻法人私章（方形的）。费用大概20元左右。-
5.到会计师事务所领取“银行询征函”：联系一家会计师事务所，领取一张“银行询征函”（必须是原件，会计师事务所盖鲜章）。如果你不清楚，可以看报纸上的分类广告，有很多会计师事务所的广告。-- 6.去银行开立公司验资户：所有股东带上自己入股的那一部分钱到银行，带上公司章程、工商局发的核名通知、法人代表的私章、身份证、用于验资的钱、空白询征函表格，到银行去开立公司帐户，你要告诉银行是开验资户。开立好公司帐户后，各个股东按自己出资额向公司帐户中存入相应的钱。- 银行会发给每个股东缴款单、并在询征函上盖银行的章。- 注意：公司法规定，注册公司时，投资人（股东）必须缴纳足额的资本，可以以贷币形式（也就是人民币）出资，也可以以实物（如汽车）、房产、知识产权等出资。到银行办的只是货币出资这一部分，如果你有实物、房产等作为出资的，需要到会计师事务所鉴定其价值后再以其实际价值出资，比较麻烦，因此建议你直接拿钱来出资，公司法不管你用什么手段拿的钱，自己的也好、借的也好，只要如数缴足出资款即可。- 7.办理验资报告：拿着银行出具的股东缴款单、银行盖章后的询征函，以及公司章程、核名通知、房租合同、房产证复印件，到会计师事务所办理验资报告。一般费用500元左右（50万以下注册资金）。- 8.注册公司：到工商局领取公司设立登记的各种表格，包括设立登记申请表、股东（发起人）名单、董事经理监理情况、法人代表登记表、指定代表或委托代理人登记表。填好后，连同核名通知、公司章程、房租合同、房产证复印件、验资报告一起交给工商局。大概3个工作日后可领取执照。此项费用约300元左右。- 9.凭营业执照，到公安局指定的刻章社，去刻公章、财务章。后面步骤中，均需要用到公章或财务章。--
土耳其的经典谚语
土耳其的经典谚语 土耳其在中世纪曾一度是世界上最强大的国家之一，她的强大绝非偶然，而是和这个民族的血液与文化有关的，下面整理了土耳其谚语，欢迎大家阅读。 土耳其谚语(热门)一小勺盐能调好一大碗汤 犬吠，而驮队继续向前。 与朋友吃喝，可是别跟他们做生意。 邻人的鸡仔如鹅;邻人的妻子娇如娥。 通红的果子招石头。 上帝也给每只笨鸟儿准备了一个矮树枝。 上帝每关上一扇门，就打开另外一千扇。 如果技能可以看会的话，那么每条狗都能开肉铺了。 “说”是耕种，“听”才是收获。 能力的话没有学校的。 土耳其谚语(最新)长远来看，吝啬鬼和慷慨人花出去的还是一样多。 饥饿的肚子是不长耳朵的。 未至溪流前，莫把裤腿卷。 每个“糟糕”背后还有个“更糟糕”。 闲散如酸醋，会软化精神的钙质;勤奋如火酒，能燃烧起智慧的
火焰。 科学的敌人，不比朋友少。 不学习的人总以后悔而告终。 真理不需要喋喋不休的誓言。 不劳动的玩乐，就象没有放盐的面包。 谎言的船开不远。 土耳其谚语翻译İnsanoğlu bir varmış bir yokmuş, dünya gelip geçicidir. 人如匆匆过客，天地亦非永恒。 Hırsızlık bir ekmekten, kahpelik bir öpmekten. 盗物一次便是贼，卖淫一回即为娼。 Ağustosta gölge kovan, zemheride karnı ovar. 夏天干活不卖力，冬天就要饿肚皮。 Akı karası geçitte belli olur. (或者) Ak göt, kara göt geçit başında belli olur. 是骡子是马，拉出来遛遛。 Duvarı nem, insanı gam yıkar. 潮湿摧墙倒，忧伤催人老。
土耳其礼品及家用电器展览会展后分析报告
展会名称：第20届2009土耳其国际家庭用品、礼品及家用电器展览会 (Zuchex) 展览时间：2009年10月15日至18日 展览地点：土耳其，伊斯坦布尔，TüYAP展览中心, 展馆名称：1号 --10号展馆 网站：https://www.wendangku.net/doc/0b6360537.html, 展会综述： 这届2009年秋季展，有超过1000间来自22个国家和 地区的企业参展，展厅规模达到10个展厅之雄伟规 模。该展是世界第四，欧洲第三的家庭用品展览会， 是第20届举办。每年分春秋两届举行，展出面积达到 60，000平方米。2008年秋季展已经有16个国家和地 区的550多家企业参展，专业买家超过45，000人次， 来自全球100个国家和地区，主要来自欧洲、美国、 中东及亚洲等地。土耳其每年官方消费品部分采购进 口额为10亿欧元，近几年越来越多的西欧买家发现该 展是个不错的产品采购资源，这部分买家的数量正呈 显著增长的趋势。由于土耳其毗邻欧亚非三大陆的特 殊地理环境，使该展成为辐射欧亚非三大陆的枢纽型 展览会。2008年春季开始该展首次设立国际展区，是 有意进军欧亚市场的出口型贸易和生产企业的绝佳良 机。 参展范围： 家用小电器，各类礼品，家居装饰品，家纺用品，餐厨用品，玻璃制品，塑料制品，陶瓷制品，灯具及照明设备。 买家分布：欧洲，南北美，亚洲，中东，非洲 新产品推荐：
藤制家居用品 Portable Grill Standard Drum Oven 背景为画的tableware 花纹典雅高尚的Dinnerware
展会情况及市场展望： 开展4天，我司展位一直是同列展位买家人流最旺，受关注度最高之处.虽然同行https://www.wendangku.net/doc/0b6360537.html,紧靠旁边，他们非常羡慕我司展位前驻足登记询盘的买家数量之多，并表示他们参该展数次，第一次见有如此的买家人流量。这次来我司登记的买家多数为各公司的President或者Import Manager,占买家比率77.83%，其余问贸易公司和采购商的Product Develop Manager。 在历史过程中，作为连接亚欧大陆的灵魂之都，伊 斯坦布尔成为丝绸之路之间的东部和西部的世界 过渡点，至今仍保持这一传统的生存延续。该枢纽 型展览会的举办，吸引了不少来自欧洲，中东，亚 洲，非洲和南北美洲的买家，对2010年这些地区 的家居和家电用品发展趋势起了至关重要的作用。环球市场展会专业展会数据分析
(完整版)个人注册公司应该选择哪种类型的
个人注册公司应该选择哪种类型的个人注册公司应该选择哪种类型的，对于初次创业的人来说，在资金、社会关系、业务渠道、经营实力等方面处于弱势，初次创业的人要经过详细的了解和计算来选择公司的组织形式，尽量选择最适合自己的公司形式注册。下面雁荡上海注册公司，对适合个人注册的几个类型进行了简要介绍和优劣对比分析。一、个人独资企业 个人独资企业是指由一个自然人投资,财产为投资者个人所有,并以其个人财产对企业债务承担无限责任的经营实体。 （一）个人独资企业其优势主要体现在: 1、设立门槛低。没有法定最低注册资本金的要求,投资人只需有申报的出资即可。 2、企业自由度大,经营管理灵活。个人独资企业财产归投资人所有,由投资人支配;投资人可以自行管理,也可以选择聘任管理或委托管理。 3、企业负税轻。个人独资企业非企业所得税纳税主体,企业所得不必缴纳企业所得税,投资人只须就个人投资所得交纳个人所得税。 （二）个人独资企业其劣势主要体现在： 个人独资企业作为非法人企业,不能以自己的财产独立承担有限责任,所以个人独资企业一旦资不抵债,投资人应以自己的全部财产偿还企业不能偿还的债务,承担的风险较大。 二、一人有限责任公司 一人有限责任公司简称一人公司，它是由一个自然人或者法人投资设立的有限责任公司。相对于个人独资企业而言，尽管投资人都是一人，但二者却存在根本的不同。一人公司是法人企业，有自己独立支配的法人财产，公司财产与投资人的个人财产严格分开，投资人以认缴的出资为限对公司承担责任，公司以自己所有的财产对债权人承担有限责任。 （一）一人公司的劣势主要体现在： 1、一人公司设立门槛比较高;公司法规定，注册一人公司，最低资本限额十万元人民币，而且必须一次缴足。 2、投资人负税较重。公司必须就其所得缴纳企业所得税，投资人从公司取
在中东做生意
如何在中东做生意 2010-05-11 11:10:39| 分类：关于中东.中国商阅读376 评论0 字号：大中小订阅 -- 关于中东市场 中东指巴林、塞浦路斯、埃及、伊朗、伊拉克、以色列、约旦、科威特、黎巴嫩、阿曼、卡塔尔、沙特阿拉伯、叙利亚、阿联酋、也门等 15 个国家。 一、市场概述 中东市场通常指环绕波斯湾和阿拉海的9个国家和周边阿拉伯国家，总人口达到5-7亿，人均年收入从阿联酋，科威特等的3-4万美元到伊朗，伊拉克，也门等国家的年人均收入5-6千美元不等，这些阿拉伯国家的轻工，日用，电子，服装基本外要依赖进口，产品的价格要求为中低要求，档次不是非常高.同时这些部分地区，几乎可以讲是一种完全纯消费的特点。中国产品在全世界以物美价廉著称，中国作为世界第一轻工，电器，服装等产品大国，以绝对优势占据整个中东市场。尽管欧美市场是目前世界上最发达、最成熟的市场，但这个市场的竞争十分激烈，商品趋于饱和，加上高进口关税及贸易壁垒的限制，后来者或中小实力的企业很难进入。纵览当今世界，唯有中东和非洲市场是一个充满商机、前景良好的热点市场。 说起中东，就不能不提阿联酋和迪拜。迪拜是阿联酋7个酋长国中的一个，位于阿拉伯半岛的东端，处于"五海三洲"中点的重要战略位置，是东西方的交通要道和贸易枢纽。每天通过迪拜转口的集装箱达到几万个，为中东第一大港口，在迪拜你可以找到全世界120国家的商人，他们常年穿梭于中东与本国，从事商品贸易。据不完全统计，阿联酋年贸易额约800亿美元，由于自然资源的匮乏，除了石油和天然气外的其它产品，从工业用原料、设备到民用生活物品均依赖进口，故阿政府一直实行开放的自由贸易政策，没有贸易壁垒，无外汇管制及其管理机构，从得到授权的银行可以无限制地获得外汇，没有征收公司或企业的利润税和营业税的规定，没有所得税、增值税、消费税和中间环节的各种税收，利润可以自由汇出。除烟、酒等极个别商品外，其它大部分商品只是象征性征收1%-4%的关税。外贸在阿联酋经济中占有重要位置。阿各类商贸公司14108家，其中外国公司680家，国有中国公司37家，自由贸易区4个。1995年，加入世界贸易组织。进口主要有粮食、机械和消费品。阿转口贸易比重较大，同100多个国家和地区有贸易关系，与40多个国家签订了双边贸易协议和避免双重征税协议。我国主要出口阿联酋的主要产品为：轻工，纺织，机电，和家用电器，由于国内厂家对阿市场的重视不够，使得出口产品的质量有所下降，直接影响到价格，目前所有出口产品的纯利润从1997年的45%，下降到17%，部分产品下降到10%左右，在2001年出口中东，仅仅到迪拜港口的货物容值达到25亿美元。 往来中东80%以上的货物要经过迪拜进行中转，同时辐射到非洲大部分国家，辐射人口达到13亿。在这里云集了非洲近30多个国家的客商，常年在这里采购日用，轻工，电器，服装，等货物。通常进口交易额度的75%转口非洲市场，20%转口周边海湾国家，5%直接在阿联酋消费。迪拜素有“中东的香港”之美誉，是阿联酋的金融经济中心，以其自由宽松的经济政策、得天独厚的地理位置、完善齐备的基础设施，迅速成为中东地区的交通枢纽和最大的货物集散地。通过迪拜，货物可转销到海湾地区、俄罗斯、东欧、非洲、地中海。目前我国产品以种类繁多、档次适中、规格齐全、价格合理颇受青睐，进一步开发潜力极大，尤其是机电五金、汽摩配件、纺织服装、轻工工艺极具竞争优势。通过迪拜，货物可转销到海湾地区、东欧、非洲、南亚。海湾地区以盛产石油天然气闻名于世界，石油天然气的储量占世界65%以上，沙漠面积占陆地面积80%以上。整个海湾地区除了石油天然气工业比较发达以外，几乎没有其它的工业。全部的工业产 品依赖进口。
土耳其概况
土耳其概况 【国名】土耳其共和国（Republic of Turkey）。 【面积】78.36万平方公里，其中97%位于亚洲的小亚细亚半岛，3%位于欧洲的巴尔干半岛。 【人口】7256万，土耳其族占80%以上，库尔德族约占15%；城市人口为4970多万，占总人口的70.5%。土耳其语为国语。99%的居民信奉伊斯兰教，其中85%属逊尼派，其余为什叶派（阿拉维派）；少数人信仰基督教和犹太教。 【首都】安卡拉（Ankara），人口447万，年最高气温31℃，最低气温－4℃。 【政体】共和制 【货币】土耳其里拉（Turkish Lira）。 【国家元首】总统阿卜杜拉·居尔（Abdullah Gül）, 2007年8月28日由议会选出，当日就任。 【主要节日】新年：1月1日；国家主权和儿童日：4月23日；青年和体育节：5月19日；胜利日：8月30日；共和国成立日：10月29日。 【简况】地跨亚、欧两洲，邻格鲁吉亚、亚美尼亚、阿塞拜疆、伊朗、伊拉克、叙利亚、希腊和保加利亚，濒地中海、爱琴海、马尔马拉海和黑海。海岸线长7200公里，陆地边境线长2648公里。南部沿海地区属亚热带地中海式气候，内陆为大陆型气候。
土耳其人史称突厥，8世纪起由阿尔泰山一带迁入小亚细亚，13世纪末建立奥斯曼帝国，16世纪达到鼎盛期，20世纪初沦为英、法、德等国的半殖民地。1919年，凯末尔领导民族解放战争反抗侵略并取得胜利，1923年10月29日建立土耳其共和国，凯末尔当选首任总统。 【政治】2002年11月，正义与发展党在土第22届议会选举中获胜，实现单独执政，结束了土自1987年以来多党联合执政的局面。正义与发展党上台后，积极推进政治、经济改革，统筹社会协调发展，取得明显成效。2007年7月，正发党以46.6%的得票率赢得大选，继续单独执政。 2011年6月，土举行第24届议会选举，正发党以49.9%的得票率赢得胜利，实现第三次连续单独执政。 【宪法】土立法体系效仿欧洲模式。现行宪法于1982年11月7日生效，是土第3部宪法。宪法规定：土为民族、民主、政教分离和实行法制的国家。 【议会】全称为土耳其大国民议会，是土最高立法机构。共设550个议席，议员根据各省人口比例经选举产生，任期4年。实行普遍直接选举制，18岁以上公民享有选举权。只有超过全国选票10%的政党才可拥有议会席位。本届议会成立于2011年6月29日，是土第24届议会。目前议会议席分布情况是：正义与发展党327席，共和人民党135席，民族行动党52席，和平民主党29席，无党派7席。 【政府】又称部长会议。本届政府是土第61届政府，成立于2011年7月13日，系正义与发展党单独执政，法定任期4年。 【行政区划】土耳其行政区划等级为省、县、乡、村。全国共分为
Global warming全球变暖全英文介绍
One of the effects of global warming is the destruction of many important ecosystems.Changing and erratic climate conditions will put our ecosystems to the test, the increase in carbon dioxide will increase the problem. The evidence is clear that global warming and climate change affects physical and biological systems. There will be effects to land, water, and life. Already today, scientists are seeing the effects of global warming on coral reefs, many have been bleached and have died. This is due to warmer ocean waters, and to the fact that some species of plants and animals are simply migrating to better suited geographical regions where water temperatures are more suitable. Melting ice sheets are also making some animals migrate to better regions. This effects the ecosystems in which these plants and animals live. Several climate models have been made and they predict more floods (big floods), drought, wildfires, ocean acidification, and the eventual collapse of many ecosystems throughout the world both on land and at sea. There have been forecasts of things like famine, war, and social unrest, in our days ahead. These are the types of effects global warming could have on our planet. Another important effect that global warming will bring is the loss and endangerment of many species. Did you know that 30 percent of all plant and animal species alive in the world today are at risk of extinction by the year 2050 if average temperatures rise more than 2 to 11.5 degrees Fahrenheit. These mass extinctions will be due to a loss of habitat through desertification, deforestation, and ocean warming. Many plants and animals will also be affected by the inability to adapt to our climate warming.
个人与企业的关系
个人与企业的关系 企业发展离不开各个方面的发展，但就个人发展与企业发展的关系而言，从某种角度来说，可以理解为鱼和水的关系。鱼儿离不开水，也就是说个人的发展离不开企业这个大舞台；水深则鱼悦，表明企业发展良好，就会给个人发展提供相对较好的条件，个人从中受益匪浅！在现实社会中，我们每个人要给自己定好位，为企业的良好发展贡献自己的一份力量。 只有在集体中,个人才能获得全面发展其才能的手段,也就是说,只有在集体发展的前提下，个人才有可能发展 集体的氛围和风格在无形中会影响到每一个人，举一个最简单的例子，就是大学的文化和历史沉淀，人们常说在北大呆两年，什么也不干，熏也给你熏出点北大的气质来；还有“近朱者赤，近墨者黑”，其实都是这个道理。 其实，说的这些很多人都是认同的，并且在意识里是存在的，但是往往却有这样的一个误区，总希望自己成长在一个优秀的集体中，却从没有考虑怎样去营造一个优秀的集体，怎样去领导一个集体，或者当面对一个集体的困难时，不愿意去承担责任。当然，这中间可能有自身性格、能力、取向等各方面的原因，但是我想从根本上来讲还是没有把集体的利益真正融入到个人发展当中去，还是没有正确的团队观念。 那什么是正确的团队观念呢？每个人的看法都可能不同，但我想至少两个方面，一是主观欲望上渴望在一个优秀的集体中，并愿意配合集体的各项活动，愿意为集体的成长进步尽一个成员的义务，希望集体的发展促进自己的成长与进步；二是愿意承担集体的责任，以集体的发展为己任，以集体成员的成长进步为己任，尽自己最大的努力促进集体的发展。其实这两个方面说简单一点就是成员意识和主人翁意识，但二者却有着本质的区别，应该是两个层次上的。 我想大学时代，最重要的集体就是班级，大多数同学对班级都是有感情的，但往往都是停留在第一层次上，都渴望自己的班级团结、向上、相亲相爱，但很少有同学主动的去营造这种氛围。其实班长和普通同学在班级建设过程中的角色定位的差别就在这里。很多同学不愿意做班长也是因为这个，不愿意去承受这种压力。 但我想，任何一个团队，任何一个集体中，如果成员只是具有第一个层次的团队观念的话，这个团队不会取得多么大的成功，这个团队的成员也不会有什么大的发展；而如果每一个人都把自己当着团队真正的主人，都在谋划团队的发展，我想团队就会越来越好，成员同样就会越来越好，这就会形成一个良性的循环。 集体的发展是每一成员都应该思考的事情，每一个人都会从集体中获得东西，有形的或无形，如果你