带时间窗的多车型多费用车辆路径问题的模型和算法

创新性地考虑了多车型车辆路径问题中不同车型具有不同的边际费用和行驶费用的问题,并同时考虑车型与任务的相容性,对带时间窗约束的多车型多费用非满载车辆路径问题,以最小化总费用为目标建立了数学模型.由于该模型的NP-hard性质,基于高费用车型的边际费用和单位行驶费用比低费用车型的相应费用都要高以及低费用车型的边际费用远大于高费用车型的单位行驶费用的思想,对该模型设计了一个启发式算法.

Time varying congestion pricing for multi-class and multi-mode transportation system with asymmetric cost functions

This paper considers the problem of time varying congestion pricing to determine optimal time-varying tolls at peak periods for a queuing network with the interactions between buses and private cars.Through the combined applications of the space-time expanded network（STEN） and the conventional network equilibrium modeling techniques,a multi-class,multi-mode and multi-criteria traffic network equilibrium model is developed.Travelers of different classes have distinctive value of times（VOTs）,and travelers from the same class perceive their travel disutility or generalized costs on a route according to different weights of travel time and travel costs.Moreover,the symmetric cost function model is extended to deal with the interactions between buses and private cars.It is found that there exists a uniform（anonymous） link toll pattern which can drive a multi-class,multi-mode and multi-criteria user equilibrium flow pattern to a system optimum when the system＇s objective function is measured in terms of money.It is also found that the marginal cost pricing models with a symmetric travel cost function do not reflect the interactions between traffic flows of different road sections,and the obtained congestion pricing toll is smaller than the real value.

Minimum Cost Multi-Path Parallel Transmission with Delay Constraint by Extending Openflow

Sometimes user has the requirement to run a high bandwidth application over a low bandwidth network. But its implementation is not easy as the traditional network transmits data with only one path where its bandwidth is lower than the demand. Although the current network technology like SDN has the ability to precisely control the data transmission in the network, but till now the standard openflow protocol does not support splitting one flow to multiple flows. In this paper, a flow splitting algorithm is proposed. The algorithm splits a data flow to multiple sub-flows by extending the openflow protocol. A multiple paths routing algorithm is also proposed to implement the multi-path parallel transmission in the paper. The algorithm selects multiple paths and minimizes the cost of transmission under the constraint of maximum delay and delay variance. The simulations show the algorithms can significantly improve the transmission performance.

COST:Coding over Spatial-Temporal Diversity for Low-Duty-Cycle WSNs

In low-duty-cycle wireless sensor networks,designers have to cope with unreliable links and limited communication capacity.In this work,we propose COST,a coding scheme that leverages spatial-temporal diversity to achieve higher energy efficiency and lower delay of packet transmissions.We particularly address long sleeping intervals in low-duty-cycle networks by exploiting multi-path diversity.Specifically,we propose to employ an erasure-coding scheme to improve reliability.With respect to energy efficiency and delivery timeliness,we formulate the problem in optimal allocation of coded blocks over multiple paths,which is then proved to be NP-hard.We further propose a near-optimal algorithm to solve the allocation problem.Through extensive simulations,we evaluate the impact of network parameters and demonstrate the effectiveness of our proposal.

Board of Directors, Independent Directors and Audit Fees： Based on the Empirical Data of the GEM of China

As one of the alternative variables of audit quality, audit fees have been researched widely in the Mainboard of China stock market, but empirical research based on the GEM （Growth Enterprise Market） of China is very few. From the perspective of GEM of China, this article observes and studies the impact of corporate governance structure represented by board of directors and independent directors on audit fees. This article selects the data of 348 listed companies in the GEM of China in 2012, proves that there is a positive correlation between the number of meetings, independent directors＇ salaries and audit fees through the use of multiple linear regression model, and accordingly proposed suggestions that improve the corporate governance structure of the GEM of China.

Housing Correlates of Under-Five Mortality in Urban Ethiopia

Little studies and analysis have been undertaken to investigate the housing determinants of under-five mortality in Ethiopia. This study, therefore, explores the impacts of urban housing variables on the levels and patterns of under-five mortality in the country based on the SPSS （Statistic Package for Social Science） file of the 2005 Ethiopian Demographic and Health Survey （EDHS）. This survey covered a sample of about 4,420 households/housing units of urban Ethiopia. The under-five deaths are computed for women in the age group 15-49 by subtracting the number of children living from children ever born （CEB） and established the proportion dead by dividing deaths by CEB corresponding to the categorical variables of housing structure, facilities, and household durables. The analytical techniques of the study included univariate, bivariate, and multivariate data analysis of the proportional variations of childhood mortality patterns being manifested by ＂bar graphs＂ with respect to housing situations as well as household durables. Amongst the categorical variables of the housing structures, facilities, and household durables with the highest no prevalence of under-five mortality levels are found to be the units of unconventional walls, thatched/leaf/reed roofing, animal dung flooring, shared pit latrine/use of bucket/bush, using kerosene, firewood/straw/charcoal for cooking, unconventional lighting, unprotected water supply, households with no durables.

Suboptimal network coding subgraph algorithms for 5G minimum-cost multicast networks

To reduce the transmission cost in 5G multicast networks that have separate control and data planes, we focus on the minimum-power-cost network-coding subgraph problem for the coexistence of two multieasts in wireless networks. We propose two suboptimal algorithms as extensions of the Steiner tree multicast. The critical 1-cut path eliminating （C1CPE） algorithm attempts to find the minimum-cost solution for the coexistence of two multicast trees with the same throughput by reusing the links in the topology, and keeps the solution decodable by a coloring process. For the special case in which the two multicast trees share the same source and destinations, we propose the extended selective closest terminal first （E-SCTF） algorithm out of the CICPE algorithm. Theoretically the complexity of the E-SCTF algorithm is lower than that of the C1CPE algorithm. Simulation results show that both algorithms have superior performance in terms of power cost and that the advantage is more evident in networks with ultra-densification.