GSM半速率技术原理及应用简介

通过对半速率技术原理的介绍，结合现场试验情况，分析了半速率技术对网络性能的影响，提出了关于开启半速率技术时网络规划方面的建议：     

用户呼叫数据在移动网络规划中的应用

简要介绍了利用移动网络里的用户呼叫历史记录进行大数据挖掘的方法;通过网络维度对现有2G/3G网络的负荷及忙的区域进行分析;通过用户维度侧重于对网络中的用户终端类型、终端能力、用户分布区域等进行分析;网络维度和用户维度两者相结合的贴近用户的网络价值分析,提高了网络规划和优化的可预见性,为精准化网络建设提供有力支撑。     

George Dantzig in the development of economic analysis

The role of optimization is central to economic analysis, particularly in its “neoclassical” phase, since about 1870, and is therefore highly compatible with the impulse behind linear programming (LP), as developed by Dantzig. LP’s stress on alternative activities fits very well with modern economic analysis. The concept of economic equilibrium, properly understood, required the central notion of complementary slackness. so central in LP.

LP was seen as a tool for actual implementation of neoclassical principles precisely at a time when the market was under attack from several directions. The economists Koopmans and Hurwicz played an important role both in stimulating the crucial development of the simplex method and in relating LP to the world of economics.

LP became widely used in national economic planning, particularly for developing countries, and for the study of individual industries, especially the energy sector. The works of Chenery and of Manne are central in these fields.

As respect for the usefulness of the market increased, the emphasis on national planning diminished and was replaced by an emphasis on equilibrium analysis, in which LP still plays a large part in the study of individual sectors, particularly energy.     

Even-aged restrictions with sub-graph adjacency

Restrictions on the size and proximity of clearcuts have led to the development of a variety of exact and heuristic methods to optimize the net present value of timber harvests, subject to adjacency constraints. Most treat harvest units as pre-defined, and impose adjacency constraints on any two units sharing a common border. By using graph theory notation to define sub-graph adjacency constraints, opening size can be considered variable, which may be more appropriate for landscape-level planning. A small example data set is used in this paper to demonstrate the difference between the two types of adjacency constraints for both integer programming and heuristic solution methods.     

On Spectrum Congestion and Capacity of Radio Links

This paper addresses the operation of radio links under mutual interference conditions, an important problem in spectrum management and radio link design. It introduces the capacity loss and isolation index as measures of effective use of radio links and radio frequency spectrum resources.     

The multi-item capacitated lot-sizing problem with setup times and shortage costs

We address a multi-item capacitated lot-sizing problem with setup times and shortage costs that arises in real-world production planning problems. Demand cannot be backlogged, but can be totally or partially lost. The problem is NP-hard. A mixed integer mathematical formulation is presented. Our approach in this paper is to propose some classes of valid inequalities based on a generalization of Miller et al. [A.J. Miller, G.L. Nemhauser, M.W.P. Savelsbergh, On the polyhedral structure of a multi-item production planning model with setup times, Mathematical Programming 94 (2003) 375–405] and Marchand and Wolsey [H. Marchand, L.A. Wolsey, The 0–1 knapsack problem with a single continuous variable, Mathematical Programming 85 (1999) 15–33] results. We also describe fast combinatorial separation algorithms for these new inequalities. We use them in a branch-and-cut framework to solve the problem. Some experimental results showing the effectiveness of the approach are reported.     

Efficient shift scheduling in the retail sector through two-stage optimization

Efficient workforce scheduling has an important impact on store profit and customer service. Standard scheduling problems do not recognize the effect of staff availability on customer sales, however, even though the latter is an important factor in the retail sector. In this paper a two-stage model is proposed for this purpose. In the first stage a sales response model is used to specify hourly staff requirements. The output of the sales response model is then used as the input of a mixed integer optimization model, which finds an optimum assignment of the staff to daily shifts. Simulations are used to validate the sales response function, and to revise the model for more accurate results. In the simulations, customer arrivals and sales response error values are generated using appropriate distribution functions. As a case study the proposed model is applied to a Turkish retailer in the apparel sector.     

A survey of berth allocation and quay crane scheduling problems in container terminals

Due to the variety of technical equipments and terminal layouts, research has produced a multitude of optimization models for seaside operations planning in container terminals. To provide a support in modeling problem characteristics and in suggesting applicable algorithms this paper reviews the relevant literature. For this purpose new classification schemes for berth allocation problems and quay crane scheduling problems are developed. Particular focus is put on integrated solution approaches which receive increasing importance for the terminal management.     

An ATM Switch Capacity Allocation Problem

In this paper, we consider a capacity allocation problem arising in the context of deploying asynchronous transfer mode (ATM) networks. Given types of ATM switches, the problem is to find an optimal allocation of capacity such that the total cost of installed switch modules is minimized, while satisfying all traffic demands. We formulate the problem as an integer programming model, which can be conceptualized as a generalized bin packing problem with capacity constraints. We then develop a surrogate constraint technique of the formulation for enhancing the representation of the model. Guided by the tight lower bound of the surrogate relaxation, we devise an effective tabu search heuristic that provides good quality solutions with guaranteed optimality. We present promising computational results that show the viability of the proposed heuristic and lower bounding methods, and that provide insights into implementation for configuring ATM switch in practice.     

Robust surgery loading

We consider the robust surgery loading problem for a hospital’s operating theatre department, which concerns assigning surgeries and sufficient planned slack to operating room days. The objective is to maximize capacity utilization and minimize the risk of overtime, and thus cancelled patients. This research was performed in collaboration with the Erasmus MC, a large academic hospital in the Netherlands, which has also provided historical data for the experiments. We propose various constructive heuristics and local search methods that use statistical information on surgery durations to exploit the portfolio effect, and thereby to minimize the required slack. We demonstrate that our approach frees a lot of operating room capacity, which may be used to perform additional surgeries. Furthermore, we show that by combining advanced optimization techniques with extensive historical statistical records on surgery durations can significantly improve the operating room department utilization.