Combining DEA with location analysis for the effective consolidation of services in the health sector

One of the most important activities of strategic planning in a health-care system is the effective allocation of scarce resources. Most of such strategies are attempting to create more efficient systems based on better organizational and management structures. Therefore, it is necessary to develop systematic models and evaluation methods that will support a strategic planning process that addresses issues such as the location of services and the effective use of resources such as equipment, funds or workforce. Such modeling approaches need to quantify the effect of changes in the location of providers, the opening or closure of providers, and the dynamic transformations of the services offered at each provider. In this paper we propose a methodology that takes into account health service provider efficiencies based on multiple measures. These efficiencies are then employed to determine health providers' locations and service allocations, which include new services distribution as well as existing services redistribution. This approach employs data envelopment analysis (DEA) and integer programming (IP) location allocation models and can be used as both an immediate evaluation tool and a long-term planning aid.     

Enhancing Concept-Based Retrieval Based on Minimal Term Sets

There is considerable interest in bridging the terminological gap that exists between the way users prefer to specify their information needs and the way queries are expressed in terms of keywords or text expressions that occur in documents. One of the approaches proposed for bridging this gap is based on technologies for expert systems. The central idea of such an approach was introduced in the context of a system called Rule Based Information Retrieval by Computer (RUBRIC). In RUBRIC, user query topics (or concepts) are captured in a rule base represented by an AND/OR tree. The evaluation of AND/OR tree is essentially based on minimum and maximum weights of query terms for conjunctions and disjunctions, respectively. The time to generate the retrieval output of AND/OR tree for a given query topic is exponential in number of conjunctions in the DNF expression associated with the query topic. In this paper, we propose a new approach for computing the retrieval output. The proposed approach involves preprocessing of the rule base to generate Minimal Term Sets (MTSs) that speed up the retrieval process. The computational complexity of the on-line query evaluation following the preprocessing is polynomial in m. We show that the computation and use of MTSs allows a user to choose query topics that best suit their needs and to use retrieval functions that yield a more refined and controlled retrieval output than is possible with the AND/OR tree when document terms are binary. We incorporate p-Norm model into the process of evaluating MTSs to handle the case where weights of both documents and query terms are non-binary.     

Multiobjective multiproduct parcel distribution timetabling: a real‐world application

Multiobjective multiproduct parcel distribution timetabling problem is concerned with generating effective timetables for parcel distribution companies that provide interdependent services (products) and have more than one objective. A parcel distribution timetabling problem is inherently multiobjective because of the multitude of criteria that can measure the performance of a timetable. This paper provides the mathematical formulation of the problem and applies the model to a real‐world case study. The application shows that without a common ground with the practitioners, it would be impossible to define the actual requirements and objectives of the company; problem definition is as important as model construction and solution method.     

基于与或图的Web服务组合的研究

现在Web服务技术的应用变得更为普及。单个Web服务只提供有限的功能,难以满足实际应用的需要。Web服务组合已经成为Web服务应用中一个非常重要的研究方面。本文提出了一种基于与或图的Web服务组合方法,该方法通过对已经访问过的服务进行标记,以服务代价作为在与或图中进行搜索的依据,缩小了搜索空间,能够快速找到一种代价很小的服务组合方法。仿真实验表明,该方法提高了Web服务组合的效率和成功率。     

Atom probe tomography characterization of radiation-sensitive KS-01 weld

The microstructure of a radiation-sensitive KS-01 test weld has been characterized by atom probe tomography. The levels of copper, manganese, nickel and chromium in this weld were amongst the highest of all the steels used in Western reactor pressure vessels. After neutron irradiation to a fluence of 0.8 × 10²³ n m⁻² (E>1 MeV) at a temperature of 288 °C, this weld exhibited a large Charpy T_41J shift of 169 K, a large shift of the fracture toughness transition temperature of 160 K, a decrease in upper shelf energy from 118 to ∼78 J, and an increase in the yield strength from 600 to 826 MPa. However, the mechanical properties data conformed to the master curve. Atom probe tomography revealed a high number density (∼3 × 10²⁴ m⁻³) of Cu-, Mn-, Ni-, Si- and P-enriched precipitates and a lower number density (∼1  × 10²³ m⁻³) of P clusters.     

基于Intel IXA1200的宽带接入服务器的设计与实现

介绍了IXAl200的体系结构，以此为基础讨论了一种局域网如何接入Internet的方法的设计与实现。在IXAl200体系结构上实现链路层协议和网络层控制协议，从而实现Internet高效接入服务器的功能。     

An approach of defending against DDoS attack

An approach of defending against Distributed Denial of Service （DDoS） attack based on flow model and flow detection is presented. The proposed approach can protect targets from DDoS attacking, and allow targets to provide good service to legitimate traffic under DDoS attacking, with fast reaction. This approach adopts the technique of dynamic comb filter, yields a low level of false positives of less than 1.5%, drops similar percentage of good traffic, about 1%, and passes neglectable percentage of attack bandwidth to the victim, less than 1.5%. The prototype of commercial product, D-fighter, is developed by implementing this proposed approach on Intel network processor platform IXP1200.     

基于图形方法的对称函数两种展开系数之间的转换

本文讨论了基于与-或-非代数系统和基于与-异或代数系统的两类基本对称函数的定义和任意对称函数在这两类对称函数完备集中的图形表示,提出了两种展开系数的图形转换方法。     

An effective algorithm for obtaining the minimal cost pair of disjoint paths with dual arc costs

Routing optimisation in some types of networks requires the calculation of the minimal cost pair of disjoint paths such that the cost functions associated with the arcs in the two paths are different. An exact algorithm for solving this NP-complete problem is proposed, based on a condition which guarantees that the optimal path pair cost has been obtained. This optimality condition is based on the calculation of upper and lower bounds on the optimal cost. A formal proof of the correctness of the algorithm is described. Extensive experimentation is presented to show the effectiveness of the algorithm, including a comparison with an integer linear programming formulation.     

Small-angle neutron scattering study on the effect of hydrogen in irradiated reactor pressure vessel steels

Hydrogen uptake can enhance the neutron embrittlement of reactor pressure vessel (RPV) steels. This suggests that irradiation defects act as hydrogen traps. The evidence of hydrogen trapping was investigated using the small-angle neutron scattering (SANS) method on four RPV steels. The samples were examined in the unirradiated and irradiated states and both in the as-received condition and after hydrogen charging. Despite the low bulk content of hydrogen achieved after charging with low current densities, an enrichment of hydrogen in small microstructural defects could be identified. Preferential traps were microstructural defects in the size range of ≈ > 10 nm in the unirradiated and irradiated samples. However, the results do not show any evidence for hydrogen trapping in irradiation defects.