Journal of Hydroelectric Engineering

水力发电学报

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2015 Vol. 34, No. 5 Published: 2015-05-25

	1	Water security situation in China and the supporting role of science and technology innovation
		LIU Ning
		As an important part of national security and a matter of sustainable economic and social development in our country, water security is in the process of our modernization drive must address the major strategic issues. Severe water shortage, water pollution, water disaster threat aggravating, serious water ecological degradation and so on is the serious situation of water security in China. Depends on knowledge innovation, technology innovation and institutional innovation, the transformation of scientific and technological achievements on water safety for the practice of building water conservancy, provide strong support for water security of China.
		2015 Vol. 34 (5): 1-3 [Abstract] ( 204 ) PDF (242 KB) ( 432 )

	4	Approach to annual runoff classification based on fuzzy set theory and set pair analysis
		DING Xiaoling，ZHOU Jianzhong，CHEN Lu，ZHAO Yunfa，LI Hui
		To consider fuzziness in river runoff, an improved method for annual runoff classification and a fuzzy classification criteria of runoff are presented by analyzing the existing classification approach based on set pair analysis. We adopted a contribution weighting factor to describe both the annual amount of runoff and its features of distribution in a year, and obtained a comprehensive membership degree of annual runoff for each class. Then, we evaluated and classified the annual runoff level relative to high and low flows using a set pair analysis method. Application to the runoff analysis of the Xiluodu station at the Jinsha River shows that this method is more effective in runoff level classification than approaches based on set pair analysis.
		2015 Vol. 34 (5): 4-9 [Abstract] ( 203 ) PDF (356 KB) ( 536 )

	10	Analysis and verification of runoff variation characteristics based on HHT method
		FAN Linlin, WANG Hongrui，LAI Wenli，YU Song
		Hilbert-Huang transform (HHT) is a new approach to analyze nonlinear, non-stationary time series. This paper presents an application of this transform to the annual runoff at the Qingyangcha hydrological station of the Dalihe River basin during 1959-2000. Using HHT, we calculated the intrinsic mode function (IMF) component and trend term Res of the response period and its HHT spectra. The results show that the runoff displays a significant downward trend with a downward rate of roughly 436980 m3/a and it takes variation periods of 29a, 15a, 6a, and 3a. Then, they were verified by using the methods of Mann-Kendall (MK) test and Mexhat wavelet transform. This shows that the HHT results agree with those by MK test and wavelet transform while HHT has a better time resolution than wavelet transform. And the MK tests detected a mutation point of the runoff series that had occurred in 1971. All the results indicate that HHT is an effective approach to nonlinear, non-stationary hydrological series and that using different methods for analysis can mine more useful information from the series and better understand hydrological processes.
		2015 Vol. 34 (5): 10-18 [Abstract] ( 175 ) PDF (776 KB) ( 572 )

	19	Minimum support area of riverhead based on regional hydro-climate factors
		SHA Yukun, LI Weipeng, FAN Jihui, CHENG Genwei
		Riverhead is a source area forming a tributary but it is difficult to determine accurately, so it is often judged by a threshold size of the catchment area above the river starting location (minimum support area). How to define this threshold is a key issue in digitization of river network, directly affecting drainage density and watershed division. Traditionally, a given constant threshold value or some empirical thresholds are used, and methods based on meteorological and hydrological conditions for determination of the catchment area threshold are lacking. This paper analyses the existing methods for determination of the threshold and the main characteristics of riverheads, and presents a new criterion that the river starting location is a cross section with mean flow rate of 0.005~0.010 m3/s in dry season. And by this criterion, we suggest a new method for threshold calculation using three hydro-climate factors: annual rainfall, annual evaporation, and minimum stream flow in arid season. Then, a series of thresholds were calculated by using the digital elevation map (DEM) of the Beishuiqu sub-basin of the Niyang River and extracting the river networks with ArcSWAT, and verified via comparison with a reference river network that had been extracted from a larger-scale digitized map. The results show that for this sub-basin, if a minimum flow Qc=0.0085 m3/s is taken as the critical support flow, a good agreement with the real river networks can be achieved and the corresponding threshold riverhead area is 4.91 km2. The suggested method considers meteorological and hydrological conditions and gives reasonable results, and thus it is significant to extraction of digital river networks in complex hydro-climate conditions.
		2015 Vol. 34 (5): 19-26 [Abstract] ( 172 ) PDF (1584 KB) ( 394 )

	27	Study of optimal reservoir operation with ECMWF ensemble precipitation forecasts
		YOU Fangfang，PENG Yong，XU Wei，LU Di
		This paper develops a runoff description model using ensemble precipitation forecasts that considers adequately uncertainty in precipitation, and also an optimal operation model of stochastic dynamic programming that maximizes the total power generation of scheduling period under the constraint of firm power. In a case study of the basin upstream to the Huanren reservoir, its optimal operation was calculated by using the ensemble precipitation forecasts from the European Centre for Medium-Range Weather Forecasts (ECMWF). Results show an increase of over four percent in power generation, demonstrating the practical value of ensemble precipitation forecasts to scheduling of reservoir operation.
		2015 Vol. 34 (5): 27-34 [Abstract] ( 252 ) PDF (1050 KB) ( 428 )

	35	Simplification method of deriving joint operating rule curves for multi-reservoir operation
		PENG Anbang，PENG Yong，ZHOU Huicheng
		Inefficiency and counter-intuitive results are often generated by using optimization algorithm alone for deriving joint-operation rule curves of large-scale multi-reservoirs. This paper describes a simplification method for deriving the rule curves via a case study of the north-line inter-basin water transfer-supply project in Liaoning Province, China. The framework of this new method was derived by considering three aspects: the basic pattern of conventional hedging rule curves for major water users of aggregation reservoirs, the mean period distribution of water surplus and shortage, and the heuristic information including operation experiences and laws. Then, we developed an optimization-simulation model using this new method. The results show that the method brings about an easier searching of optimal solution in optimization algorithm and improves rationality and practicability of joint rule curves.
		2015 Vol. 34 (5): 35-43 [Abstract] ( 196 ) PDF (560 KB) ( 456 )

	44	Improvement on power generation scheduling charts of chronological series method in Design for Operation of Reservoirs
		WANG Ping
		A scheduling chart of power generation, if designed by the specifications Design for Operation of Reservoir, usually has unreasonable points that cannot be removed even by repeated testing and modification. This article presents an improvement method and measures for eliminating such points and modifying the method recommended in the specifications. This new method adopts successive calculation of long series and unifies the calculations of one-year regulation and multi-year regulation of a reservoir. It can calculate the lower power output curve accurately and avoid the overlap between low output area and guarantee output area, improving the accuracy of power generation scheduling curves. Application to actual projects indicates that the method improves power generation scheduling chart in meeting different requirements of low output and firm output. The chart can be completed in one-time success with no need for repeated testing and modification and meet the reliability requirement of power design.
		2015 Vol. 34 (5): 44-50 [Abstract] ( 177 ) PDF (269 KB) ( 438 )

	51	Analysis on variation of soil erosion and sediment yield in Three Gorges reach
		XU Tao，ZHOU Man，LI Changchun
		The Three Gorges reach is an area of potential soil and water loss owing to its huge topographic relief and heavy precipitation, so the sediment eroded away from it takes a significant proportion of the sediment inflow of the Three Gorges reservoir. This portion, however, has always been neglected since the preliminary design because of the difficulty in its quantitative estimation. This article presents a calculation of soil erosion in each of three typical years (2000, 2007 and 2010) using the GIS spatial analysis technology and a RUSLE model of statistical method to lay a basis for quantitative estimation. By this calculation, we found out that the average soil erosion modulus is 2474, 2126 and 1844 t/（km2?a）respectively, and that the estimated amount of soil erosion in the three years are 145, 124 and 108 million tons respectively.
		2015 Vol. 34 (5): 51-56 [Abstract] ( 176 ) PDF (800 KB) ( 357 )

	57	Influence of inlet form on hydraulic jump in stilling basin with shallow water cushion
		LI Lianxia, LIAO Huasheng, LIU Dewei, LIU Da, QI Lijian, SHEN Huanrong, YI Wenmin
		Experimental tests were conducted to examine the influence of inlet form on hydraulic jump in stilling basin with shallow water cushion in asymmetric outlet condition, based on a physical model of the energy dissipater No. 3 in the flood discharging tunnel of Luding hydropower plant. Comparison of flow patterns shows that the inlet form that has significant impact on the water cushion, is a crucial factor to the formation and stability of hydraulic jump in the case of shallow cushion in stilling basin. The multi-steps inlet is advantageous when the cushion is deep enough and the inlet main flow close to the bottom, while it helps to develop surface-flow patterns when the main flow is away from the bottom and the cushion too deep, especially in the case of small jet angle at the inlet. In contrast, an arc inlet can help the inlet main flow be close enough to the bottom to ensure the formation of hydraulic jump inside the basin with appropriate water cushion, but the jump is probably unstable and asymmetric because of the high speed flow reflected by the end sill, which can be solved by modifying the inlet form from transitional to continuous.
		2015 Vol. 34 (5): 57-65 [Abstract] ( 146 ) PDF (7485 KB) ( 82 )

	66	Study on control conditions of highest surge in upper surge chamber of pumped storage power stations
		WANG Bingbao，YANG Jiandong，ZHANG Xinchun，ZENG Wei
		There is a high probability to operate successive load rejections when more than two units share one main pipe, which is generally adopted at pumped storage power stations. This condition could be a control condition of the highest surge in upper surge chamber. This paper derives an implicit formula for calculating the highest surge following load rejection at any time using the basic equation of wave motion of surge chamber, and calculates the surge-tunnel discharge relationship for the condition occurring at the worst surge wave superimposition owing to successive load rejections or other unfavorable superimposition conditions. By the results of the implicit formula taking this relationship as initial condition, we come to the conclusion that the control condition is shifting from load-increment-then-rejection condition toward successive load rejections as the hydraulic resistance coefficient of throttled surge chamber increases. Numerical simulations of an example pump-storage project are included for verification of the conclusion.
		2015 Vol. 34 (5): 66-71 [Abstract] ( 178 ) PDF (323 KB) ( 350 )

	72	Study on stability of waterpower-speed control system for hydropower station with two upstream series surge chambers
		TENG Yi，YANG Jiandong，GUO Wencheng，CHEN Jieping
		Installation of two upstream series surge chambers is a significant and feasible measure for peak pressure control. This paper presents a study on the stability of waterpower-speed control system for hydropower station with such a measure. For this system, we developed a complete mathematical model including diversion pipeline, surge chamber, hydraulic turbine, speed governor, and generators, and derived a comprehensive transfer function and linear homogeneous differential equation that describe the system's dynamic characteristics. The effects of fluid inertia in water diversion system and the surge chamber parameters on stability conditions are also analyzed in this paper using stability domains. The main conclusions are as follows. When the control system reaches the same stability domain as that with one upstream surge chamber, the total cross-sectional area of the two chambers is greater than that of one chamber. If the second chamber or the one closer to the plant is smaller, a greater total area is required to reach the same stability domain. The smaller the ratio of pipe flow water inertia between the two chambers over that between the pipe intake and second chamber, the smaller the difference between the total cross-sectional area of two chambers and that of one chamber system.
		2015 Vol. 34 (5): 72-79 [Abstract] ( 196 ) PDF (843 KB) ( 328 )

	80	Study on effects of asymmetrical flaring gate pier Y-shapes on length of aerated cavity and its negative pressure
		HOU Xiaoxia，YANG Jurui，XIONG Changxin
		This paper presents a study on the effects of asymmetric flaring gate pier Y-shapes on the length of steps-aerated cavity and its negative pressure. We adopted a RNG turbulence model and a VOF model to simulate the water vapor two-phase flows, and used a PISO velocity-pressure coupling algorithm for iterative solution of geometry reconstruction scheme with the unsteady flow approach. For a stepped spillway with asymmetrical Y-shape flaring gate piers, the study covers a flow domain from the reservoir up to the end sill of downstream stilling basin, and focuses on numerical simulations of the length of cavity and its negative pressure in the conditions of gate piers' contraction ratios of 0.598, 0.497 and 0.445. Experimental tests were conducted with the aerated cavity lengths being measured. Comparison of the simulated and measured results shows a good agreement of the cavity length with calculation errors in the range of 9.7%, indicating accuracy and reliability of the present method in successful calculation of cavity length and pressure distribution. The simulations show that as the pier contraction ratio decreases, the cavity length is reduced, and that the length of cavity at the smaller contraction side is four to five times greater than that at the other side. With a decreasing pier contraction ratio, negative pressure on the steps aerated by the air cavity is reduced, but its covering area on the steps expands gradually. At the outer edge of all the steps occurs a negative pressure that takes the lowest value on the vertical face of the first step at the spillway entrance.
		2015 Vol. 34 (5): 80-87 [Abstract] ( 182 ) PDF (576 KB) ( 538 )

	88	Direct calculation formula of conjugate depths for parabola-shaped channels
		DAI Shubing，LIU Hansheng，YANG jijian
		The equations of conjugate depths for the channels with a parabolic cross section are implicit functions too complicated to solve directly. This study adopted identical transforms to simplify the equations of hydraulic jump in semi-cubic, square, and cubic parabola-shaped channels. Then for all these shapes, we derived dimensionless conjugate depths x and y as well as their relationship, using the fact that critical depth is between these two depths. We adopted the 1stopt software and its genetic algorithm to optimize and fit the parameters of established nonlinear models, and finally obtained direct calculation formulae of conjugate depths for all the channel shapes. Error analysis and example calculations show that the relative errors of x and y calculated by these formulae are in the ranges of 0.05% and -0.06%, 0.07% and -0.10%, and -0.0858% and 0.0985% for the semi-cubic, square, and cubic parabola-shapes respectively. The formulae are clear in physical concepts, convenient in calculation, and applicable to a wide range, and thus they would provide a theoretical basis and practical tool for design and operation management of parabola-shaped channels.
		2015 Vol. 34 (5): 88-94 [Abstract] ( 197 ) PDF (540 KB) ( 439 )

	95	Characteristics of energy dissipation of M-shape stepped spillways
		WANG Lei，DIAO Mingjun，ZHU Runye，YAN Jin
		Energy dissipation ratio of stepped spillway is gradually reduced as its unit discharge increases, and it involves various problems of operation under large unit discharges. Previous studies of stepped spillway have focused on step size, spillway slope, energy dissipation, and various other issues, but very few on how to optimize the shape and layout of spillway steps. This paper describes a new type of stepped spillway that uses flat rectangular step sides and plane layout shapes of alphabet "M" to overcome the problems of operation under large discharge. Numerical simulation method of turbulent flow is used to study the energy dissipation features of this new spillway. Results show that under large unit discharge, the M-shape stepped spillway can be aerated more fully and its negative pressure area on the top step faces is smaller. And its dissipation rate is higher, because vortices of various scales occur near the step faces, causing three-dimensional local flow patterns.
		2015 Vol. 34 (5): 95-102 [Abstract] ( 182 ) PDF (895 KB) ( 329 )

	103	Experimental study on temperature of water released from multi-level orifice intake
		GAO Xueping，REN Qingyu
		Water in large reservoir is often featured with evident temperature stratification over depth with a significant variation by roughly 20℃ from surface to bottom. Multi-level orifice intake is a typical device for taking water from reservoirs for irrigation, and its major function is to control the temperature of released water within a range suitable for crops. The existing studies on the design of such intakes and their temperature regulation are lacking. In this study, physical model tests were conducted by adjusting submergence and flow rate to model thermal stratification of reservoir and explore the relationship among released water temperature , reservoir water temperature, intake submergence and intake flow rate. Results show that released water temperature is lowered as intake submergence increases while raised as intake flow rate increases. In addition, released water temperature also depends on the temperature distribution over reservoir water body. This study would lay a basis for design, operation and management of multi-level orifice intakes.
		2015 Vol. 34 (5): 103-107 [Abstract] ( 181 ) PDF (705 KB) ( 433 )

	108	Study on free surface-pressurized flows in tailrace tunnel with sloping ceiling by 1D-3D coupling approach
		AN Hua， YANG Jiandong
		During transient process of hydropower station, mixed flow of free surface and pressurized regimes usually occurs in the tailrace tunnel with sloping ceiling, and its flow patterns is relatively complicated owing to its features of three dimensionality. Accurate simulation of such free surface-pressurized flows is crucial to regulation guarantee parameters. This paper describes simulations of this mixed flow using 1D-3D coupling approach, and compares the results with those of virtual slot approach. We also discuss the difference of these two methods in modeling the interface of free surface and pressurized flow regimes and its oscillatory motion as well as their results of minimum hydrodynamic pressure in draft tube, demonstrating the flaws of virtual slot approach.
		2015 Vol. 34 (5): 108-113 [Abstract] ( 214 ) PDF (1751 KB) ( 345 )

	114	Analysis on the definition of bankfull stage by geometric criterion
		HE Li,YAN Yunxia, YAN Ming
		Bankfull discharge is morphologically significant, as it is identified as a key parameter for studying river morphology, sediment motion, flood dynamics, and their ecological impacts. Identification and determination of bankfull stage is critical to both development of regional curves and calculation of bankfull discharge but doing this in-situ could be practically difficult and subjective. This paper compares two identifying approaches, one based on geomorphic features in-situ, and the other on geometric criterion of surveyed channel cross-sections. For the geometric criterion, we collected the data of cross sections measured at the Huayuankou hydrology station in 50 years to compare its four methods, namely Wolman (WOL), Williams (WIL), Riley (RIL) and Wang (B/H). Analysis shows that to identify the bankfull stage in a multiple-branch wandering reach, effective channel width is a necessary parameter even all the cross-sectional areas below various stages are known. Of these four methods, WIL and RIL are insensitive to effective width, while the bankfull stages estimated by WOL and B/H tend to increase with narrower effective width. In application to the cross sections of Huayuankou, the bankfull stages by WIL are relatively higher, especially those for the period after 1980, while the stages by WOL and B/H are relatively lower.
		2015 Vol. 34 (5): 114-118 [Abstract] ( 240 ) PDF (294 KB) ( 541 )

	119	Statistical damage model for marble under uniaxial compression based on SEM testing scheme
		LI Xiaojuan，NI Xiaohui，ZHU Zhende
		The micro-fracturing process of marble samples under uniaxial compression, taken from the surrounding rock of the Jinping II cascade hydropower station, was recorded by using meso-mechanical testing schemes based on the scanning electron microscopy (SEM). Fracture spacing of these samples is analysed herein by statistical theory and compared with macro-fracturing process, and the probability distribution of micro-fracture spacing is generalized by an extreme-value distribution of damage parameters. Appling the basic principle of energy dissipation, we developed a damage model of macro- and meso-fracture information in the framework of irreversible thermodynamics and applied it to simulation of stress-strain relationships. The results show that all the calculated stress-strain curves fall within the range between two experimentally measured envelope curves. The damage parameter D that contains macro- and meso-fracture information is more sensitive to damage condition than the ones and containing macro-fracture information only. And the growth of these parameters presents prominent staged features.
		2015 Vol. 34 (5): 119-123 [Abstract] ( 144 ) PDF (511 KB) ( 344 )

	124	Study on effects of complex foundation on dock shiplock structure
		HU Shilong，LIU Xiaoping，CAO Zhouhong，LUO Pengfei，ZHOU Xiaoling，ZHANG Yu
		A comparative analysis on the effects of complex foundation on dock shiplock structure was made by using nonlinear finite element simulations of three types of foundation, i.e. complex soil of prototype, homogeneous type, and simplified type, focusing on the deformation and stress distribution of the shiplock structure. The analysis shows the differences of these three models in the settlement of foundations and structures and their effects on deformation and internal force distribution. Significant differences between the models of complex foundation and homogeneous soils in calculation of deformation and stress, reveal the importance of foundation features. Similar results of the simplified model and complex soil model indicate that if a simplified model is reasonable, it can give good results and simplify calculation.
		2015 Vol. 34 (5): 124-130 [Abstract] ( 185 ) PDF (505 KB) ( 267 )

	131	Numerical assessment of seepage control effects of Hongping pumped storage power station
		ZHOU Bin，LIU Sihong，JIANG Zhongjian，Hu Yiling，YANG Mingshan
		To evaluate the seepage-proof efficiency of the Hongping pumped storage power station, this paper presents an analytical method which integrates the secondary subdivision technology of drain holes and the modified node virtual flow method based on a whole model of the dam basin and underground power house. This model uses the secondary subdivision to simulate complex seepage control measures, such as densely distributed drainage holes, and calculates the exact solution at frozen points by considering the contribution of given nodes to the flow of transition elements. It adopts the method of enlarging transitional zone to determine the location of seepage free surface. Thus, this analytical method offers a convenient and accurate tool for the seepage problems with complicated seepage-control measures. This paper also discusses a technique of specifying groundwater boundary, which is useful for seepage control optimization of similar projects.
		2015 Vol. 34 (5): 131-139 [Abstract] ( 179 ) PDF (1436 KB) ( 448 )

	140	Quantitative analysis of process of concrete CT test under uniaxial compression
		FANG Jianyin，DANG Faning，LI Xiaorong，YANG Chao
		Most of the existing CT technologies used for study of the mechanical properties of concrete at mesoscopic level are limited to a stage of qualitative observation and statistical analysis, lacking the capability of quantitative analysis based on mathematical theory. This article presents an application of the set theory to damage-fracture evolution of concrete specimens in CT test, and develops a new quantitative method for analysis of damage process using CT test data. By the damage-fracture evolution theory and the definition of λ1~λ2 intercepted sections, the CT image is divided into a crack area (P0~0.35), a hardened cement paste area (P0.35~0.7), and an aggregate area (P0.7~1), so that different components of concrete in each subarea can be examined quantitatively. Then, the quantitative variations of P0~0.35, P0.35~0.7 and P0.7~1 can be calculated with the change of CT test loading for the whole image region or any interested sub-regions. The results show that this new method is successful in quantitative describing the strain localization of specimens in failure process and provides an effective tool for study of concrete failure.
		2015 Vol. 34 (5): 140-146 [Abstract] ( 156 ) PDF (1656 KB) ( 301 )

	147	Investigation on turbine cavitation signals analysis based on Hilbert-Huang transform
		XUE Yangang, WANG Han
		Cavitation of water turbine units is one of the factors influencing the stability and efficiency of their operation. Cavitation phenomena that occur in a running turbine unit are not easy to observe directly and acoustic signal monitoring is an effective way of the cavitation study. Traditional Fourier transform and wavelet transform are two commonly-used methods for analysis of narrow-banded low-frequency signals, but they are difficult to cover high-frequency components of water turbine cavitation broadband signals. This paper describes a new self-adaptive Hilbert-Huang transform (HHT) method that uses EMD decomposition to extract the physically meaningful signal components of turbine cavitation mode, and explores cavitation identification using HHT. Experimental tests show that this method is fast in diagnosis and better in generalization performances. Thus, it is a suitable method for cavitation fault diagnosis of hydroelectric unit.
		2015 Vol. 34 (5): 147-151 [Abstract] ( 143 ) PDF (371 KB) ( 551 )

	152	Critical turning point and maximum water hammer in impulse turbine under two-segment linear valve closure
		YOU Qiusen, LAI Xu
		The turning point of two-segment linear closure law is commonly determined by using only the rated working condition of a impulse turbine, which neglects the fact that the maximum water hammer (MWH) happens at partial load rejection. This paper analyzes the MWH behaviors at linear valve closure and derives two inferences for the case of general needle-valve closure. First, for each linear closure region, the local MWH always happens at the end time of its line segment if its time duration is no less than that of one phase; second, the MWH pressure in the whole needle-closure region equals the greatest value of all the first-phase water hammers in all working conditions if in any working conditions no negative water hammer occurs at the nozzle until its total shutdown. Using these two inferences, we further derive a critical turning point formula and come to the conclusion that if the three discrimination formulas are true, then the two regional MWHs used as the basis of this derivation are also the MWH pressures in the whole region of needle valve closure.
		2015 Vol. 34 (5): 152-158 [Abstract] ( 169 ) PDF (303 KB) ( 357 )

	159	Study on sand erosion angle in centrifugal pump based on burst structure of near-wall turbulences
		NIU Quan
		Sand abrasion in fluid machinery remains at the exploratory stage in spite of tremendous previous efforts in experimental, numerical and theoretical studies in recent years. This paper presents a preliminary study on sand abrasion in centrifugal pump from the perspective of turbulent coherent structure in near-wall region. We derive the near-wall sand velocity normal to the wall using the BBO equation of sand motion, and obtain the sand velocity along the local flow in a sweep considering the behaviors of burst structure. Then, we can calculate the impact angle of sand particles on the impeller surface of a centrifugal pump. The results show that in a centrifugal pump, the small angle cutting damage of small sand particles to impeller surfaces is caused by the sweep of coherent structures in near-wall turbulences. This conclusion is supported by previous experimental tests in literature.
		2015 Vol. 34 (5): 159-165 [Abstract] ( 174 ) PDF (336 KB) ( 317 )

	166	Economic impact assessment of large-scale hydropower project based on computable general equilibrium model
		MA Jing, LIU Yu
		Economic impacts of large-size multi-functional hydropower project are complex and interactive, which are transferred via economic industrial chain and interregional economic linkage. Comprehensive assessment must take a perspective of integrated economic system. This paper presents a multi-regional computable general equilibrium (CGE) model for assessment on the project economic impacts from multi-dimension perspectives, and discusses its application to analysis of the impact mechanism and transfer path induced by hydropower development in the upper Chuan river. The results indicate that the hydropower projects in this valley has outstanding benefits to regional economy, which are reflected in various indicators such as consumption, investment, import, export, GDP, and employment. From a spatial perspective, the impacts descend along the distance from the project location.
		2015 Vol. 34 (5): 166-171 [Abstract] ( 202 ) PDF (283 KB) ( 409 )

	172	Study on activity criticality in the project network planning
		JI Zhongkai, YANG Weixuan, WANG Renchao, TIAN Yu
		Effects of different activities on the expected completion time of a project are not the same. Based on this fact, one of the most important issues in project management is to determine important activities and the amount of effort that should be assigned to control them, thereby completing the project successfully. In this regard, several classical criticality indexes, including activity criticality probability (ACP), activity cruciality index (ACI), and significance index(SI), are thoroughly compared and analyzed herein. Due to the shortcomings of all these indexes, a new one, namely activity importance index (VES), is adopted to measure the importance of project activities. Moreover, based on the fact that expending effort on activities and controlling them actively can result in a shorter mean duration of the project, this paper puts forward a thought that the project managers allocate their own energy according to the critical index of each activity. Finally, we develop a network planning software, C#-NETSIMU, using Visual C# and apply it to analysis of a case project. This study would help project managers for reasonable project control.
		2015 Vol. 34 (5): 172-180 [Abstract] ( 140 ) PDF (450 KB) ( 300 )