An analysis of the length of hospital stay for cataract patients in Japan using the discrete-type proportional hazard model

We analyze the length of hospital stays of patients hospitalized for cataract and related diseases (Diagnosis Related Groups (DRG) 2041) in Japan, utilizing the data pertaining to 3436 patients on whom one-eye lens operations are performed. We use the discrete-type proportional hazard model to analyze variables that may affect the length of stay.     

A real options approach for evaluation and justification of a hospital information system

Nowadays healthcare organizations globally recognize the importance of investing in information technologies to improve the quality of care delivery and reduce costs. The key drivers of healthcare sector such as continuously improving healthcare standards and insurance systems have introduced new requirements for hospitals, which in return provided a solid ground for decision-makers to consider implementing hospital information systems that are customized and improved versions of enterprise resource planning (ERP) systems designed according to the needs of the healthcare sector. The conventional discounted cash flow methods ignore the value of managerial and strategic flexibility inherent in these investments, which is crucial for justification of the investment decision. This study introduces a real options-based methodology which overcomes the limitations of traditional valuation methods and enables decision-makers to value an ERP system investment incorporating multiple options. The option valuation model developed in this study extends the binomial lattice framework to model a hospital information system (HIS) investment opportunity with compound options. The potential application of the proposed model is illustrated through evaluation of a real-world HIS investment.     

一种新型三相流测量系统的研制

利用成熟的单相流测量仪的基本原理 ,研制了一种新的三相流在线检测仪及其系统。应用热扩散法来测量气液比 ,设计的灵巧电容探头来测量油水比 ,该仪器可适合各种不同生产条件的油田的三相流测量     

缺货不补的随机存储系统的建模与仿真

基于(s,S)策略,讨论了缺货不通过到达的订货进行补充的随机存储系统.假定需求量、需求发生的间隔、以及提前时间都为随机变量,建立了系统的数学模型.给出库存总费用和缺货率的计算公式,将二者加权平均得到策略的综合系数.设计了系统仿真运行框图,在各种费用参数给定后,利用计算机仿真和综合系数来选定最优存储策略.     

电子产品故障维修仿真培训系统设计与开发

传统的电子产品故障维修技能培训多采用物理破坏的方式来模拟产生电子产品故障。这种非柔性且具破坏性的考核系统使得培训工作效率低、培训成本高、资源浪费等问题。为此,本文提出了应用智能嵌入式控制器柔性且非破坏地模拟电子产品故障的新方法,并开发了一套电子产品故障维修技能智能化培训系统原型。     

An apparatus and a method for determining the slip resistance of shoes and floors by simulation of human foot motions

An apparatus to measure the coefficient of kinetic friction (μ_k) between the shoe sole and the underfoot surface was constructed, and a method including criteria to evaluate the risk of slipping during walking was developed. The apparatus is a prototype stationary step simulator capable of simulating the movements of a human foot and the forces applied to the underfoot surface during an actual slip, and the drainage capability of the contact surface between the shoe sole and the flooring when different lubricants or contaminants are used.

The apparatus consists of a movable artificial foot controlled by a computer with the aid of three hydraulic cylinders. The frictional force (F_μ), the normal force (F_N) and their ratio (μ_k = F_μ/F_N) are measured with a two-way force platform when the foot slides along its surface. Two separate gait patterns, heel-slide (μ_k1) and sole-slide (μ_k2) gait pattern, are used for the evaluations. The method classifies studied shoe, lubricant and underfoot surface combinations into five slip resistance classes according to the measured μ_k1 The slip resistance assessments are specified with some complementary safety criteria, e.g., the ratio μ_k1/ μ_k2 The reliability of the developed measurement method was assessed in an international comparison test. According to available results discussed in this paper, our method seems to be valid and the slip resistance measurements seem to be repeatable.     

Development of a decision support system for neuro-electrostimulation: Diagnosing disorders of the cardiovascular system and evaluation of the treatment efficiency

The study describes a preliminary stage of the decision support system development for physician performing neuro-electrostimulation of neck neural formations for patients suffering from cardiovascular system disorders. The arterial hypertension was used as the clinical model of the disorders. The study consisted of two steps: diagnosing of the arterial hypertension and an evaluation of the treatment efficiency during the neuro-electrostimulation application. For the diagnosing part, a clinical study was conducted involving heart rate variability signals recorded while performing tilt-test functional load. Heart rate variability signal is an indirect mean of accessing autonomic nervous system functioning. Disturbances of the autonomic nervous system are essential in pathology of arterial hypertension. Performance of different machine learning techniques and feature selection strategies in task of binary classification (healthy volunteers and patients suffering from arterial hypertension) were compared. The genetic programming feature selection and quadratic discriminant analysis classifier reached the highest classification accuracy. Best feature combinations were used to evaluate treatment efficiency. Predictions based on the selected heart rate variability features have a high level of agreement with the arterial pressure dynamics. The results indicate the potential of the proposed decision support system.     

Development of a mobile robotic system for working in the double-hulled structure of a ship

Shipbuilding processes involve highly dangerous manual welding operations. Welding ship walls inside double-hulled structures presents a particularly hazardous environment for workers. This paper describes the “Rail Runner X” (RRX), a new robotic system that can move autonomously inside the walls of a double-hulled ship and automatically execute the required welding processes. The RRX robotic system is composed of a mobile platform and a welding robot consisting of a 3P3R serial manipulator. The robot is used to weld U-shaped trajectories located between two longitudinal stiffeners. The mobile platform enables traverse movements onto neighboring longitudinal stiffeners. The entire cross section of the robotic system is small enough to be placed inside the double-hulled structure via a conventional access hole from the outside shipyard floor. The overall engineering design process that led to the final robot solution developed is presented in this paper, including kinematic analysis data and experimental results for verifying the autonomous movement and welding performance.     

An agent-based simulation system for concert venue crowd evacuation modeling in the presence of a fire disaster

A key activity in emergency management is planning and preparation for disaster. If the right safety measures are implemented beforehand, harmful effects can be significantly mitigated. However, evaluation and selection of effective measures is difficult due to the numerous scenarios that exist in most emergency environments coupled with the high associated cost of testing such scenarios. An agent-based system employs a computational model of autonomous interacting agents in an environment with the purpose of assessing the emergent behavior of the group. This paper presents a prototype of a computer simulation and decision support system that uses agent-based modeling to simulate crowd evacuation in the presence of a fire disaster and provides for testing of multiple disaster scenarios at virtually no cost. The prototype is unique in the current literature as it is specifically designed to simulate a concert venue setting such as a stadium or auditorium and is highly configurable allowing for user definition of concert venues with any arrangement of seats, pathways, stages, exits, and people as well as the definition of multiple fires with fire and smoke dynamics included.     

An expert system for the identification of environmental impact based on a geographic information system

The identification and assessment of the environmental impacts of engineering projects is an essential step in studies on environmental impact (IES). There are methods that allow both tasks to be performed and methods that allow each of them to be carried out separately. Normally, traditional methods are used to identify and evaluate environmental impacts, such as matrices, cause-effect network diagrams or check lists. Here we report the configuration of an expert system as a tool that allows environmental impacts to be identified. The expert system is based on a geographic information system to configure the knowledge base, the inference motor and the user interface. The knowledge base comprises declarative knowledge (structured in an alphanumeric and spatial database from official cartographic information) and procedural knowledge (via heuristic rules that superimpose project actions over environmental factors). We then describe the application of the expert system to the study of the environmental impact of the R-3 motorway in the Community of Madrid, Spain. As results, running the expert system allows the identification of environmental impacts on environmental factors defined at the 1:5000 and 1:25000 cartographic scales. Finally, analysis of the results or conclusions allows the validity of the use of graphic expert systems to be compared for the identification of environmental impacts.     

Assessment of system reliability for a stochastic-flow distribution network with the spoilage property

In supply chain management, satisfying customer demand is the most concerned for the manager. However, the goods may rot or be spoilt during delivery owing to natural disasters, inclement weather, traffic accidents, collisions, and so on, such that the intact goods may not meet market demand. This paper concentrates on a stochastic-flow distribution network (SFDN), in which a node denotes a supplier, a transfer station, or a market, while a route denotes a carrier providing the delivery service for a pair of nodes. The available capacity of the carrier is stochastic because the capacity may be partially reserved by other customers. The addressed problem is to evaluate the system reliability, the probability that the SFDN can satisfy the market demand with the spoilage rate under the budget constraint from multiple suppliers to the customer. An algorithm is developed in terms of minimal paths to evaluate the system reliability along with a numerical example to illustrate the solution procedure. A practical case of fruit distribution is presented accordingly to emphasise the management implication of the system reliability.     

Development of a systematic checklist for the human factors evaluation of the operator aiding system in a nuclear power plant

In the safety systems review of the Korean nuclear power plants, the Human Factors Program Plan for the OAS (Operator Aiding System) has been executed mainly by an expert review. The reviewers had to integrate all the relevant sources of information and make judgement based on their own criteria. Consistency and thoroughness of this process was always in question and a systematic approach to correct these problems was in need. The purpose of this work was to design a methodology for supporting an effective and efficient ergonomic evaluation of the user interface of the OAS. By collecting and systematically structuring all the critical considerations in the human factors review process, an ergonomic evaluation checklist for the CFMS (Critical Function Monitoring System) in an MCR (Main Control Room) was designed and implemented in this study. Application of the developed checklist was used during the licensing review process for the CFMS of the Ulchin unit 3&4. Efficiency and effectiveness of the human factors review process was enhanced significantly with the aid of the integrated checklist and the standardized evaluation format developed in this study.

Relevance to industry

Human factors review process is an integral component of the safety of a nuclear power plant. The methods and procedures developed in this study will provide valuable support for the enhancement of the safety and usability of the human interface of the nuclear power plant.     

一阶系统自伴随条件和Lagrange函数的构造

重新研究一阶系统变分法逆问题,修正了某些文献关于一阶微分方程组自伴随条件的失误,导出了把一阶系统化为自伴随形式的变换矩阵所满足的方程,列出了构造自伴随一阶系统Lagrange函数的两种方法.举例说明所得结果的应用.     

A new method for computing a solution of the Cauchy problem with polynomial data for the system of crystal optics

A new analytical method for solving an initial value problem (IVP) for the system of crystal optics with polynomial data and a polynomial inhomogeneous term is suggested. The found solution of the IVP is a polynomial. Theoretical and computational analysis of polynomial solutions and their comparison with non-polynomial solutions corresponding to smooth data are given. The applicability of polynomial solutions to physical processes is discussed. An implementation of this method has been made by symbolic computations in Maple 10.     

板翅式换热器翅片流阻快速检测系统设计

铝制钎焊板翅式换热器是一种高效、紧凑式换热器,广泛用于空气分离设备、天然气处理、天然气液化、烯烃装置等石油化工的低温分离装置、hyco装置、氦液化、氢气液化装置及动力机械等。翅片是板翅式换热器的核心部件,其加工质量的下降,会直接导换热器阻力降的升高、传热效率下降,进而造成设备运行能耗的增大。因此,控制加工成型的翅片流阻在一定范围内,是有效保证翅片加工质量的关键。针对传统的基于风机的换热器阻力测试装置雷诺数上限低、试件拆装繁琐、测试效率低等缺点,采用高压气体作为测试气源,配合液压驱动的试件固定装置,开发了一套可实现板翅式换热器翅片流阻快速检测的装置。通过开发基于C#及SQL Server数据库技术的上位机测控软件,实现了测试数据的实时采集、处理和曲线显示。测试实验结果显示,该检测装置系统重复性误差均可保证在3%以内,满足宽雷诺数、高精度的翅片阻力特性测量要求,为实现翅片加工质量检测提供保障。     

Extrapolation for solving a system of weakly singular nonlinear Volterra integral equations of the second kind

This article discusses an extrapolation method for solving a system of weakly singular nonlinear Volterra integral equations of the second kind. Based on a generalization of the discrete Gronwall inequality and Navot's quadrature rule, the modified trapeziform quadrature algorithm is presented. The iterative algorithm for solving the discrete system possesses a high accuracy order O(h ^2+α). After the asymptotic expansion of errors is proved, we can obtain an approximation with a higher accuracy order using extrapolation. An a posteriori error estimation is provided. Some numerical results are presented to illustrate the efficiency of our methods.     

Using the fuzzy-ellipsoid method for robust estimation of the state of a grid system node

Constructing a workload model for a node of a Grid system is considered in terms of control theory. A node is represented as a linear dynamic object acted upon by perturbations with unknown statistical properties. Fuzzy set estimates are used to evaluate the state of the object. They ensure the robustness of the algorithm proposed and its usability under the lack of a priori information on the unknown vector and the inaccuracy of current measurements. Translated from Kibernetika i Sistemnyi Analiz, No. 6, pp. 67–74, November–December 2008.     

永磁型无轴承电机悬浮系统的H∞鲁棒控制

为了提高永磁型无轴承电动机悬浮系统的稳定性和抗干扰能力,从运行原理出发,对悬浮系统提出了基于混合灵敏度的H∞鲁棒控制.通过选取适当的灵敏度和补灵敏度加权函数,设计了H∞控制器.应用该控制器实现了基于转子磁场定向控制的永磁型无轴承电机悬浮控制系统.仿真结果表明,所提出的H∞控制器具有良好的抗干扰能力和鲁棒稳定性,性能优于常规PID控制器.最后进行了实验研究,证明了该控制方法的有效性.     

An improved algorithm for the computation of structural invariants of a system pencil and related geometric aspects

In this paper we propose a new recursive algorithm for computing the staircase form of a matrix pencil, and implicitly its Kronecker structure. The algorithm compares favorably to existing ones in terms of elegance, versatility, and complexity. In particular, the algorithm without any modification yields the structural invariants associated with a generalized state-space system and its system pencil. Two related geometric aspects are also discussed: we show that an appropriate choice of a set of nested spaces related to the pencil leads directly to the staircase form; we extend the notion of deflating subspace to the singular pencil case.     

A convergence analysis of the Adomian decomposition method for an abstract Cauchy problem of a system of first-order nonlinear differential equations

In this article, we study some fundamental results concerning the convergence of the Adomian decomposition method (ADM) for an abstract Cauchy problem of a system of first-order nonlinear differential equations. Under certain conditions, we obtain upper estimates for the norm of solutions of this system. We also obtain results about the error estimates for the approximate solutions by the ADM and discuss their applications.