西南交通大学学报

Dynamic Analysis of Key Design Parameters for Ballastless Track of High-Speed Railway

CAI Cheng-Biao, XU Peng

2010, 23(4): 493-497. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](1790)

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Abstract:
The key design parameters for ballastless track of high-speed railway were analyzed using the theory of train-track coupled dynamics. The parameters under study include the design wheel load, wheel load for fatigue check, track stiffness, supporting stiffness of subgrade in the subgrade-bridge transition section, uneven subgrade settlement, deflection angle of rail surface, and change rate of rail deflection, and their values suggested by dynamic analyses are 3. 0 times as large as the static wheel load, 1. 50, 20 30 MN/ m, 500 1 000 MPa/ m, and less than one thousandth of the wave length of uneven subgrade settlement, 1. 5, and 0. 3 mm/ m, respectively.

Dynamic Frequencies and Complex Modal Motion of Mass-Spring-Damping Rotating System

LIU Zhan-Fang, ZHANG Kai, YAN Shi-Jun

2010, 23(4): 498-501. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](805)

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In order to provide a basis for researching the dynamic behavior of engineering structures in a centrifugal and vibration compound environment, dynamic equations for a mass-spring-damping rotating system with two degrees-of-freedom were set up, and the eigenfrequencies and complex modal vectors of the system were calculated. The complex decomposition of the complex modal vectors were carried out to obtain the expression of complex modal motion. The research result shows that the mass- spring-damping rotating system has dynamic frequencies and two complex modes. The eigenfrequencies of the system are related to its rotation speed and influenced by centrifugal softening and Coriolis damping. Coriolis damping makes the system eigenvectors be complex modal vectors and mass point motion be a polarized circle to show that Coriolis damping produces a motion coupling. Coriolis damping is not real physical damping, so it does not result in the attenuation of free vibration of the system.

Model Experiment of Construction Process of Long-Span Steel Truss Bridge

FAN Liang, GONG Chang-Long, CHEN Si-Tian

2010, 23(4): 502-507. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](1638)

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To probe into the mechanical behavior of the main construction stage of Chaotianmen Yangtze River bridge and enhance its safety during the construction, a model test with a scale ratio of 1 to 40 was carried out to whole simulate the construction processes of this bridge. The construction technologies for the bridge were researched, and the distribution of stresses in main bars was measured and analyzed. A numerical simulation was carried out to verify the test. The comparison between the measured stresses of the model bridge and the actual bridge shows that model test is a reliable tool in investigating the construction process of a long-span steel truss bridge. The tensile and compression stresses of the bridge occur in the state of the maximum cantilever with single-row cables and do not exceed the limits in the criterion. Multi-step conversion from flexible ties to rigid ones is more smooth and feasible than one-time conversion.

Calculation Method of Bending Crack Width in RC Beams Strengthened by Bonding Steel Plate

SHAN Cheng-Lin

2010, 23(4): 508-513. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](1160)

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In order to control the bending crack width of reinforced concrete ( RC ) beams strengthened by bonding steel plate, the crack generation mechanism before and after reinforcement was analyzed. The developing behavior of cracks was investigated through the whole loading process of six simply-supported RC beams strengthened with steel plate. Based on the existing calculation methods for crack width of RC beams, a two-stage calculation method of crack width was proposed. Moreover, the theoretical calculating values were compared with the measured values of crack width of the test beams in different loading stages. The results show that after a RC beam with cracks is strengthened by bonding steel plate, the original cracks develop firstly because of the changes of its cross-section geometric properties and load condition due to reinforcement. The calculation of the maximum crack width under bending loading should be divided into two parts, and then the two separate calculation results are superimposed to accord with the actual loading state. The control position of the maximum crack width is at the original crack nearby the center of gravity of steel bars, while not at a new crack

Experimental Investigation of Wedge-Anchor Parameters for CFRP Tendons

CHUge Ping, QIANG Shi-Zhong, HOU Su-Wei

2010, 23(4): 514-520. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](1049)

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In order to apply carbon fiber reinforced plastics (CFRP) tendon to bridge engineering,a wedge-anchor system for CFRP tendons was designed and tested. This system consists of one metal sleeve, four steel wedges and one steel barrel. Orthogonal tests of wedge-anchor parameters were conducted to investigate their influences on the anchorage performance of the wedge-anchor system. These parameters are the material and thickness of the sleeve, the indented space of the wedges and the level of presetting load. Furthermore, the anchorage performance of the wedge-anchor system was checked by CFRP tendons with higher strength and larger diameter. The experimental results show that these parameters have a significant influence on the anchorage performance. Compared with a wedge- anchor system with a copper sleeve, a wedge-anchor system with an aluminum sleeve has a large advantage. The anchorage performance of the wedge-anchor system with an aluminum sleeve thickness of 0. 8 mm, a presetting load of 100 kN and a wedge indented space of 10 mm is optimal, and its anchorage efficiency can reach to 95. 5%. This wedge-anchor system can be used to CFRP tendons with at least a diameter of 9 mm and tensile strength of 2 500 MPa.

Seismic Dynamic Responses of Plane Sliding Rock Slope

LUO Gang, HU Xie-Wen, ZHANG Yao

2010, 23(4): 521-526. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](1186)

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In order to investigate the stability-loss mechanism of a cataclinal rock slope under earthquake loading, the fatigue strength theory was used to investigate the changes of its mechanical properties under the action of the loading. Seismic waves were simplified as elastic waves to generate equivalent static stresses on a structural plane, and a stability-loss criterion about cataclinal rock slope sliding along the structural plane was obtained. Through taking Tangjiashan landsliding in the Wenchuan earthquake as an example, the rationality of the stability-loss criterion was verified. The research result indicates that sliding of a cataclinal rock slope along a structural plane depends mainly on the dip angle and internal friction angle of the structural plane, the wave impedance of rock masses on the both sides of the structural plane and the incident angle of seismic waves, and the transverse wave is the main factor causing the stability-loss of cataclinal rock slopes. To the Tangjiashan landsliding, the most dangerous incident angle is 0'and 10'to the longitudinal wave and 10'and 20' to the transverse wave.

Problems about Engineering Geology of High-Grade Railway Route Selection in Complicated Mountainous Areas

WU Guang, XIAO Dao-Tan, JIANG Liang-Wen, QU Ke

2010, 23(4): 527-532. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](1203)

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In order to scientifically carry out high-grade railway route selection in complicated mountainous areas, some major engineering geological problems in railway route selection were put forward. These problems are the gravitational process and movement of substance in high-mountain gorge areas, the crustal deformation and fault vibration mechanics, the engineering geological route selection of large elevated railway with a large difference in elevation, and the rock mass deformation and substance movement of deep-seated tunnels and so on. Based on the construction cases of the new railway lines in mountainous areas in China, several new research topics on the engineering geology of high-grade railway in complicated mountainous areas were advanced. They are the theory, principle and method of tunnel location selection and the slope stability evaluation of tunnel portal, and the location selection and slope stability evaluation of bridge sites in alpine-gorge areas.

Digital Processing of Unmanned Aerial Vehicle Image and Its Application in Reconstruction of Wenchuan Earthquake-Hit Areas

LU Heng, LI Yong-Shu, LI He-Chao, HE Jing, REN Zhi-Ming

2010, 23(4): 533-538. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](1258)

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In order to solve the difficulty in real-time acquisition of remote sensing data in multi-cloud regions, acquisition and digital processing methods of UAV (unmanned aerial vehicle) remote sensing images were discussed on the basis of the characteristics of high image resolution and good flexibility of low-altitude UAV remote sensing, and a three-dimensional image visualization process was discussed. For the reconstruction planning and design needs of Wenchuan earthquake-hit areas, the model designed for the reconstruction was introduced into the environment of a three-dimension geographic information system directly. The experimental results show that compared with satellite remote sensing data, UAV remote sensing images can provide rich geometric and semantic information in three- dimensional visualization. Combination of a design model and three-dimensional terrain scene can reproduce the design results in real-time, avoid the limitation and one-sidedness of the thinking brought about by two-dimensional graphics in a complex environment, and improve the true expression of design effects.

Improved Collaborative Optimization Algorithm

ZHANG Jing, LI Bai-Lin, ZHANG Wei-Hua, LIU Yong-Jun

2010, 23(4): 539-543. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](1263)

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In order to improve the computational efficiency of the conventional collaborative optimization ( CO), an improved collaborative optimization algorithm based on the Kriging model (Kriging-CO for short) was proposed. In this algorithm, the approximate optimization model at the system level is constructed with the Kriging model, and is updated by uniform design combined with confidence regions. The Kriging-CO was verified through the optimization of a classical function and the design of a speed reducer, and the optimization models were solved using the sequential quadratic programming algorithm. Numerical results show that the Kriging-CO can improve the computational efficiency. For the complex speed reducer design, the Kriging-CO, compared with the CO, reduced the number of iterations in the optimization computation by about 50%.

Effect of Dynamic Load Coefficients on Fatigue Damage of Welded Components for 160 km/ h Wagon Bogie

ZHOU Zhang-Xi, LI Fei, HUANG Yun-Hua, AN Qi, LI Zhi-Qiang, PAN Shu-Peng

2010, 23(4): 544-548. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](1277)

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In order to verify the fatigue strength of welded components for 160km/ h wagon bogie, a numerical simulation for the fatigue damage of dangerous welded joints in the main structures of the welded frame and bolster was made using structural finite element method (FEM) and Palmgren鄄Miner linear cumulative damage rule, in accordance with the determination method of fatigue test loads stated in UIC510-3 and the welded joints fatigue strength S-N curves provided by International Institute of Welding (IIW). The results show that the roll coefficient change has little effect on fatigue damage, while the bounce coefficient change has remarkable effect on fatigue damage. When carrying out fatigue tests of welded frame and bolster for strength verification, the roll coefficient can be taken as the standard value 0. 22 directly, the bounce coefficient should be larger than the standard value 0. 30, and is recommended to be 0. 33 preliminarily.

Influence of Wear of Wheel Profile on Dynamic Performance of EMU

LI Yan, ZHANG Wei-Hua, ZHOU Wen-Xiang

2010, 23(4): 549-554. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](1250)

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The shapes and diameters of each wheel of an electric multiple unit (EMU) were measured regularly by a WPD wheel profilometer, and the measured profiles were classified into 5 profile鄄wear conditions. Dynamic simulations were performed with a multi-body dynamics software to analyze the dynamic performance of the EMU under the 5 profile-wear conditions, in which the structural parameters of the vehicle and the specifications of the railway lines were considered. The simulation results show that the equivalent conicity should not be larger than 0. 4 for a critical speed of over 400 km/ h, the running safety and curving performance are adversely affected significantly if the wear depth exceeds 2 mm, and there are increases in the sperling index by 54% and in the lateral wheelset force by 100% under the worst profile-wear condition.

Impedance Matching and Operation Characteristics of YNvd-Connected Transformer

CHEN Min-Wu, LI Qun-Zhan, JIE Shao-Feng, ZHANG Li-Yan

2010, 23(4): 555-560. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](883)

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In order to further apply YNvd-connected transformer, a new three-phase three-winding balance transformer, in the traction power system of electrified railway, a strict mathematical model for the transformer was set up based on the magnetomotive force balance equations, the winding connection equations, the output-port equations and the voltage transfer equations, and the design requirement for ideal balance performance of the transformer was discussed. In addition, power system impedance was converted, and output voltage equations and two-phase equivalent circuit were given. The research results show that impedance mismatch will result in zero-sequence current and zero-sequence voltage in different grounding modes of a YNvd-connected transformer, and that short-circuit current for traction substation is determined by the power system impedance, leakage impedance and impedance matching.

Probabilistic Load Flow for Urban Rail Traction Power Supply Based on Monte Carlo Simulation

LIU Wei, LI Qun-Chen, TANG Bing, CHEN Min-Wu

2010, 23(4): 561-567. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](982)

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In order to research the uncertainty of urban rail traction load flow distribution, a Monte Carlo simulation method for the calculation of probabilistic load flow (PLF) was presented based on the unified AC/ DC power flow algorithm. This method constitutes the probability distribution of train position from the position-time graph of train running. The probability distribution of departing time interval is obtained in light of the organization of train operation. With the Monte Carlo simulation, the positions and corresponding powers of trains can be achieved by random sampling. By unified calculation of AC/ DC power flow, the probability distribution functions of node voltage and power can be attained. The examples shows that probabilistic statistical characteristics of traction network voltage and traction load of substation can be achieved with this method.

Low-Power Encoding Method for Data Interface of Color CIS

LIU Yi, YANG Yin-Tang, WEN Bo

2010, 23(4): 568-573. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](802)

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To efficiently reduce the dynamic power dissipation of data interface of color CMOS (complementary metal-oxide-semiconductor) image sensor (CIS), signal activity of the data interface was analyzed. Based on high correlation and low activity of upper 6 bits of the same-color pixel signals, an encoding method was proposed. With this method, whether the upper 6 bits of the current interface signal are held is determined by comparing the current pixel signal with the last same-color pixel signal to decrease the signal activity of the data interface obviously. The simulation results indicate that the dynamic power dissipation of the interface is reduced by 24. 2% with the proposed method.

Method for Verifying the Correctness of Train Control System Design

CAO Yuan, TANG Tao, LUO Dan, MU Jian-Cheng

2010, 23(4): 574-579. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](1004)

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To verify the correctness of a train control system design in the development stage, a formal method, which is based on RAISE (rigorous approach to industrial software engineering) and can be used for system modeling, description and verification, was proposed. For the tracking operation between two trains of CTCS-3 (China train control system level 3), domain models of the system were established by adopting feature-oriented domains. After extending and improving the domain models using RAISE specification language (RSL ), a final description of the tracking operation between two trains was formed. With the axioms described by RSL and reasoning rules of RAISE, the system design of CTCS-3 was verified correct in the context of tracking scene between two trains.

SINS/ GPS Integrated Navigation System for High-Speed Trains

ZHONG Xiao-Chun, ZHANG Hai-Tao, JIANG Xiang-Dong, LI Yuan-Zhong

2010, 23(4): 580-584. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](1223)

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To achieve a high navigation accuracy for a high-speed train, an integrated navigation system was proposed based on SINS/ GPS ( strapdown inertial navigation system/ global positioning system). Error sources coming from SINS and GPS were analyzed respectively. Furthermore, a corresponding algorithm was designed. Numerical results show that compared with SINS, the proposed integrated navigation system has high navigation accuracy and reliability and avoids increase of the inertial system error with time.

Spin Iteration Quantum Search Algorithm

ZHOU Ri-Gui, CAO Jian

2010, 23(4): 585-588. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](921)

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In order to improve the searching efficiency of the Grover algorithm, a new quantum search algorithm was presented based on the Grover algorithm. This quantum search algorithm makes full use of the structural information of states, and spin quantum gates are designed in light of different initialized quantum states and searched ground states, then the new quantum gates are used to spin iteration. The research shows that compared with the Grover algorithm, the presented algorithm decreases iteration times. The feasibility and validity of this algorithm are verified through practical examples.

Algorithm for Error-Tolerant Semantic Matching of Heterogeneous Graphics

SHI Nian-Feng, WANG Guo-Qiang, TANG Wei-Qing

2010, 23(4): 589-595. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](1103)

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In order to realize matching of 2D and 3D heterogeneous graphic data, an algorithm, named as MSMGE, for error-tolerant semantic matching of heterogeneous graphic data was presented based on the computer supported cooperative work in plant design. With this algorithm, the undirected-graph-like is used to represent the engineering properties and topological relations of 2D and 3D graphic data to smooth away the heterogeneity of the graphic data. And then, the semantic expression is adopted to describe the semantic relations among vertexes and edges in the undirected- graph-like to transform the semantic matching of heterogeneous graphic data into largest common subsequence error-tolerant matching. Lastly, the graphic partitioning based on engineering semantics, the semantic normalization and the semantic pruning are adopted in order to reduce the complexity of MSMGE. The research result shows that with the presented algorithm, the matching precision can exceed 90%.

Robust Stability of Impulsive Cohen-Grossberg Neural Networks with Reaction-Diffusion Terms

SHI Ji-Zhong, XU Xiao-Hui, ZHANG Ji-Ye

2010, 23(4): 596-602. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](1281)

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The global exponential robust stability of impulsive Cohen-Grossberg neural networks with reaction-diffusion terms at the equilibrium point was studied by applying a smooth boundary lemma, stability theory of vector Lyapunov function, and the mathematical induction. It was assumed that the activation functions satisfy the Lipschitz condition. The sufficient condition for global exponential robust stability of the system is that the value of the expression composed of incidence matrices, gain functions, reaction-diffusion functions, and activation functions of the neural networks is less than 0-

Performance Optimization of Collaborative Design Network Based on Service-Oriented Architecture

CAI Hai-Ni, WEN Jun-Hao, JI Jie

2010, 23(4): 603-608. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](910)

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In order to optimize the service performance of collaborative design network, an improved enterprise service bus(ESB) model with a layered service registry and QoS-based dynamic message routing was proposed in service-oriented architecture. By setting up a tree-like hierarchy among the service containers, this model uses a depth-first search to implement lookup service and narrow the search area to a minimal subtree with the service request container and service registry container as its leaves. This enhances the efficiency of local registry access to reduce the request load and network overhead of the central bus. Besides, a weighted quality of service (QoS) algorithm is adopted in the model for analysis of the current and historical measurement data, so that high-quality dynamic services are achieved. The results of application to the collaborative design system in a survey and design enterprise show that the improved ESB model reduces the average response time of the current global service registry by more than 30% under heavy access concurrency, and can automatically adjust the message route to regain a good working condition when the quality of network services is getting worse. Therefore, the efficiency of the collaborative design system is improved.

Effects of Array Errors on Fast Direction Finding Performance in Non-cooperative Passive Detection

LIU Zhi-Qiang, MA Hong-Guang

2010, 23(4): 609-614. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](835)

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Theoretical analyses were performed by applying the methods such as matrix norm and Taylor series, and so on, to quantitatively study the fast direction finding performance of a non- cooperative passive detection system with array errors, such as antenna pattern error, array element position error, mutual coupling error and channel error. The estimation error ranges of the target direction mapping angle were determined for ideal and real arrays, and the effects of array errors on beam forming were studied. It is concluded that the estimation error of the target direction mapping angle is not sensitive to the array errors. Simulation results show that the deviation and mean square deviation in estimation of the target direction mapping angle are less than 0. 015 rad for a 16 element unified linear array when the maximum relative error in beam amplitudes caused by array errors is 6. 5% and the signal to noise ratio is -20 dB.

Improved Count Method of Train Sorting Schemes

CHEN Chong-Shuang, WANG Ci-Guang, JIAN Bing-Yi

2010, 23(4): 615-620. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](828)

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In order to ensure the punctual departure of fully loaded originating trains, the count method of train sorting schemes for dispatcher to make stage plan in marshalling yard was studied. Using the theory of dynamic wagon-flow allocating, default events were explicitly expressed according to the correspondence between the inequivalent sorting scheme and regular arrangement; and the properties of the default events were discussed. On this basis, an improved count method of the inequivalent sorting schemes for a single train was obtained by following the maximum sorting principle and the first-come first-sorted rule, and then the improved count method of compatible inequivalent sorting schemes for multiple trains departing by stage was obtained similarly. The results of a computational example show that the improved algorithm, by making full use of the information of sorting intervals and sorting amounts, can reduce the search space by 28. 6%, and simultaneously reduce the computation complexity.

Markov Chain Queuing Model for Signalized Intersections with Stochastic Vehicle Arrivals

JIANG Yang-Sheng, HU Lu, PU Yun

2010, 23(4): 621-626. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](899)

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To overcome the limitation of the existing models for intersection queuing analysis in which vehicle arrivals are assumed to obey a particular distribution law, a general queuing model for signalized intersections with fixed cycle and stochastic vehicle arrivals was established using the embedded Markov chain technology. The model program and the simulation program for model verification were written using LINGO software embedded in the Excel environment. The numerical results of a case study show that, the average queue length calculated by the Markov chain queuing model is much close to the actual survey result, and has an error of 0. 14% compared with the stochastic simulation result; the queue lengths obtained by the model are identical to the actual survey and stochastic simulation results at the percentiles ranging from 50% to 65%, and have a maximum relative error of 3. 85% at other percentiles.

Personalized Service Strategy of Travel Information Based on Multi-agent Negotiation

AN Shi, CUI Na, XU Hang

2010, 23(4): 627-634. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](975)

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In order to satisfy the travel information service demand of individual users and solve the road network equilibrium assignment problem, a personalized information service strategy based on multi-agent negotiation was proposed using utility theory and multi-agent modeling technology. In this model, individual users, information issue units, and the traffic system manager are treated as different agents, and the benefit equilibrium between the individual users and the traffic system manager is attempted to be realized through negotiation among the agents. Then, the influences of the information service strategy on the individual users-travel time and the whole network performance were analyzed through Starlogo simulation under 30 negotiation service modes, designed with 5 road network saturations and 6 service acceptance ratios. The simulation results showed that the optimal flow saturation of road network for negotiation service was 0. 95, and the optimal service ratio was 60%.

Experiment and Numerical Simulation of Micro-injection Moulding

CHENG Zhi-Jiang, BARRIERE T, LIU Bao-Sheng, GELIN J C

2010, 23(4): 635-638. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](1568)

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Experiment and simulation were performed to study the feedstock fluidity and replication ability of micro-mould cavity. The experiment was conducted with a specially designed mould on a micro-injection system. The experimental results show that micro-injection parts in a size of 5 mm伊 1. 5 mm伊0. 8 mm were well replicated under the following injection parameters: the temperatures of polypropylene feedstock and the mould were 220 益and 40 益, respectively, the injection flow and time were 20 mm3 / s and 1 s, respectively, and the pressure holding time was 10 s. The simulation was performed with different wall boundary conditions using a self-developed simulation program that is based on the fully vectorial explicit algorithm. The simulation results under the wall slip conditions agreed reasonably with those of the experiment, verifying the existence of wall slip.

Microstructure Analysis of Vacuum Getter PdO Powder

CHEN Shu-Jun, WANG Rong-Shun

2010, 23(4): 639-642. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](1081)

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In order to study the H2 adsorption mechanism of PdO powder in the vacuum multilayer insulated tank, adsorption and desorption of high purity N2 with PdO powder were carried out at 77 K using a Micromeritics ASAP2010 automated instrument, and the microstructure of the PdO powder was analyzed. Experimental results showed that the N2 absorption isotherm of the PdO powder belonged to type 郁, and the initial stage of the isotherm could be explained by two-constant BET (Brunauer- Emmett-Teller) equation. An abrupt increase in the adsorbance occurred to the middle part of the adsorption isotherm because of capillary condensation. There was a hysteresis loop between the adsorption isotherm and the desorption isotherm. The saturated absorption was achieved when the relative pressure of N2 arrived at 0. 9. The PdO powder was mainly of mesoporous structure. The pores were tubular in shape and open at both ends. The specific surface area of the PdO powder was 14. 669 m2 / g; the total pore volume was 0. 030 984 cm3 / g; and the pore size, with a mean size of 8. 449 nm, was distributed in the range of 1. 700 to 20. 000 nm,

Pricing Strategy of Logistics Service Suppliers under Risk-Aversion

CUI Yi, ZHANG Jin, SHI Lu

2010, 23(4): 643-649. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](967)

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In order to reflect the effect of risk aversion of actors on the pricing strategy of a supply chain system, a supply chain model, in which manufacturers and logistics service suppliers both are risk averse, was established under the hypothesis that the market demands are influenced by the prices. The utility function was derived by certainty equivalent method to depict the risk-averse feature of the logistics service suppliers and manufacturers. As a result, the following was revealed: In decentralized decision-making, when the logistics service suppliers are risk neutral, the optimal logistics price is independent of the risk preference of the manufacturers; and when the logistics service suppliers are risk averse, the optimal logistics price, as the increasing function of the risk-aversion degree of manufacturers but the decreasing function of the risk-aversion degree of logistics service suppliers, will be smaller than that with risk-neutral suppliers. In centralized decision, the supply chain system will produce residual profits when the manufacturers are risk neutral. Loss of profits will be caused, however, when the manufacturers are risk averse and the risk-aversion degree exceeds a critical value. In this case, the logistics service suppliers and manufacturers should adopt decentralized decision. In contrast, if the risk-aversion degree of the manufacturers is below the critical value, the supply chain system will produce residual profits, and centralized decision should be selected.

Venture Capital Portfolio Based on Allocation of Capital and Management Inputs

PENG Fei, SHI Ben-Shan

2010, 23(4): 650-654. doi: 10. 3969/ j. issn. 0258-2724.

[Abstract](1407)

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A method and its model to incorporate both management and capital inputs into venture capital portfolio decision-making were presented following Markowitz's portfolio theory. In the method, management inputs are seen as an important factor closely related to the return from a venture. An exponential influencing coefficient function of management inputs was presented. A simplified venture capital portfolio model and a portfolio risk function were also presented for easy application under assumption that venture firms are not relevant

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2010 Vol. 23, No. 4