Hsing Luh - Academia.edu (original) (raw)

Papers by Hsing Luh

International journal of operations research, 2010

Operations research for health care, Mar 1, 2017

Progressions of chronic diseases can be modeled as Markov processes. Frequently, the model parame... more Progressions of chronic diseases can be modeled as Markov processes. Frequently, the model parameters are concluded based on distinct short-term clinical studies because of the difficulty of observing the entire progression process in one clinical study. Though this piece-by-piece approach provides a global picture to the disease progression process, it could lead to unrealistic results under in-depth analysis. For instance, without careful calibration, patients' life expectancy computed from the model might be longer than that of the general population. Such results usually arise from that the effect of population mortality is not sensible or not well included in these short-term clinical studies. For chronic diseases with which patients may experience a long chain of successive states, this inaccuracy is more obvious. Beck and Pauker propose that the population mortality may be integrated into a disease progression model in their work. Their method provides a solution to the aforementioned difficulty. However, their approach to integrate the population mortality into the model implicitly assumes that the population mortality solely affects the transition probabilities for transitions to the death state and for self-transitions remaining in the initial states. They do not explain why only these two types of transitions are affected by the imposed population mortality. From realistic situations, no matter what state transitions patients experience, they are all under the risk of death caused by population mortality. Based on this observation, a new modeling approach is proposed in this study. The proposed approach assumes that population mortality independently affects all state transitions of a Markov model. This extends Beck and Pauker's idea and makes their method more reasonable. The proposed approach is applied to disease progression analysis of chronic hepatitis B virus (HBV) infection and considered for further applications. Specifically, with the natural history of chronic HBV infection originally described by a coarse Markov model, a new model is developed by calibrating the coarse model with the proposed method. Numerical results show that the new model can obtain realistic estimates to patients' life expectancy and survival probabilities. Meanwhile, the concept of first hitting time can find its interesting application in deriving the probabilities for patients' first experiencing critical medical status during a specified duration. This delivers valuable information to chronic HBV patients. The model's possible extensions such as its application to different countries and taking patients' risk factors into account are also discussed for future study.

Lecture Notes in Computer Science, 2019

In this paper, we investigate the nonhomogeneity of state space for solving retrial queues throug... more In this paper, we investigate the nonhomogeneity of state space for solving retrial queues through the performance of the M/M/S retrial system with impatient customers and S servers that is modeled under quasi-birth-and-death processes with level-dependent transient rates. We derive the analytic solution of multiserver retrial queues with orbit and develop an efficient method to solve this type of systems effectively. The methods proposed are based on nonhomogeneity of the state space although this queueing model was tackled by many researchers before. Under a weaker assumption in this paper, we study and provide the exact expression based on an eigenvector approach. Constructing an efficient algorithm for the stationary probability distribution by the determination of required eigenvalues with a specific accuracy, we develop streamlined matrices of state-balanced equations with the efficient implementation for computation of the performance measures.

Journal of the Operations Research Society of China, Oct 30, 2020

This issue of Journal of the Operations Research Society of China is a special one focusing on re... more This issue of Journal of the Operations Research Society of China is a special one focusing on recent developments in Operations Research (OR): Theory and Applications. This special issue makes a significant contribution to OR in a rapidly changing environment. All participants of the 13th International Symposium on Operations Research and its Applications were cordially invited to submit their papers to this special issue. It was also open to all researchers of OR and its related areas. Eight papers were accepted for publication after rigorous reviewing processes. These papers included recent theoretical and applied contributions in various fields of OR and related topics. Short descriptions of these submissions are as follows. Tatsuo Oyama presents an overview paper: Looking for and Aiming for an Asian OR Applicable to the Public Sector. In this paper, at first, the history of OR, especially its application to public sectors is briefly described; then the characterization of using OR as a scientific method for decision making is presented. Further, OR activities in Japan are introduced, emphasizing three major roles: (i) quantitative data analysis, (ii) mathematical modeling analysis, and (iii) theory building analysis. An example for each of these three roles is then described. Xiushuang Wang, Jing Zhu, Shunfu Jin, Wuyi Yue, and Yutaka Takahashi present a virtual machine allocation scheme with a sleep-delay, establish and demonstrate a corresponding mathematical model for the performance analysis and evaluation of network resource in a cloud environment. Further, a two-dimensional Markov chain B Wuyi Yue

International journal of information and management sciences, Jun 1, 2016

This paper proposes a tiered inspection system for airport security, wherein passengers are divid... more This paper proposes a tiered inspection system for airport security, wherein passengers are divided into three classes based on historical security records. A two-dimensional Markov process and a Markov modulated Poisson process (MMPP) queue were used in the formu- lation of the security inspection system. Simulated annealing was then used to obtain near- optimum solution for the model. The efficacy of the proposed model was evaluated using the arrival data of passengers at Taoyuan International Airport and other two international airports. A comparison with two conventional queueing models with regard to the average waiting time demonstrated the effectiveness of the proposed security inspection system in enhancing service efficiency and boosting the level of security.

International journal of operations research, 2004

⎯We consider a queueing model with finite capacities. External arrivals follow a Coxian distribut... more ⎯We consider a queueing model with finite capacities. External arrivals follow a Coxian distribution. Due to the limitation of the capacity, arrivals may be lost if the buffer is full. Our goal is to study the probability of blocking. In order to obtain the steady-state probability distribution of this model, we construct an embedded Markov chain at the departure points. The solution is solved analytically and its analysis is extended to semi-Markovian representation of performance measures in queueing networks.

International Journal of Computers and Their Applications, Apr 1, 1997

Journal of The Chinese Institute of Industrial Engineers, Nov 1, 1999

Journal of Personalized Medicine, Apr 22, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Journal of integrated design & process science, Oct 12, 2022

We present a decision support model for patient-centered precision surveillance that assists clin... more We present a decision support model for patient-centered precision surveillance that assists clinicians and patients for the whole disease prospect to provide a single operational framework of whole type 2 diabetic person care management while introducing experts in the loop modeling that facilitates data collection. Based on real-world data, the scientific computation shall be adopted with experts’ experiences for providing the patient health education and accessing complication risks thereby easily delineating disease pathways. A decision tree technique is used to build a single framework consisting of every possible diabetes complication in the decision process. Coping with the complex medical system for the prevention of diabetes and diabetic complications, a patient-centered framework gives the patient interactive, transparent and useful information for better communication in the decision process that includes experts’ experience as well as the value of the prediction generated from population-based data.

The subject of this thesis is the development of a novel technique to investigate optimal control... more The subject of this thesis is the development of a novel technique to investigate optimal control problems in queueing systems. Dynamic Programming (DP) or Stochastic Dominance (SD) arguments are the traditional techniques in the study of optimal queueing control problems, but they are not applicable to models with fairly complex state and action spaces. Therefore, another technique based on Linear Programming (LP) theory is developed. A queueing network with heterogeneous servers is treated successfully using LP arguments. We apply the LP methodology to the problem of assigning customers to one of several parallel heterogeneous multiserver queueing systems. The decisions involve both routing an arriving customer to one of parallel queues and scheduling the waiting customers to corresponding idle servers. Our intention is to determine the optimal rule for selecting such decisions in routing and scheduling so as to minimize the average delay per customer in the system. We show that t...

Value in Health, 2020

the good follow-up of diabetes patients in Sweden with continuous treatments adaptations to keep ... more the good follow-up of diabetes patients in Sweden with continuous treatments adaptations to keep HbA1c low. Conclusions: Progression of HbA1c is slower with the SNDR equation. We advise to use this equation to do health policy analyses where treatment changes are inherent to the policy. To define HbA1c progression in costeffectiveness analysis, we advise to use the UKPDS68 equation, which is a better representation of the progression without treatment adaptations.

Information

Health services research and managerial epidemiology, 2022

There are several challenges in diabetes care management including optimizing the currently used ... more There are several challenges in diabetes care management including optimizing the currently used therapies, educating patients on selfmanagement, and improving patient lifestyle and systematic healthcare barriers. The purpose of performing a systems approach to implementation science aided by artificial intelligence techniques in diabetes care is two-fold: 1) to explicate the systems approach to formulate predictive analytics that will simultaneously consider multiple input and output variables to generate an ideal decision-making solution for an optimal outcome; and 2) to incorporate contextual and ecological variations in practicing diabetes care coupled with specific health educational interventions as exogenous variables in prediction. A similar taxonomy of modeling approaches proposed by Brennon et al (2006) is formulated to examining the determinants of diabetes care outcomes in program evaluation. The discipline-free methods used in implementation science research, applied to efficiency and quality-of-care analysis are presented. Finally, we illustrate a logically formulated predictive analytics with efficiency and quality criteria included for evaluation of behavioralchange intervention programs, with the time effect included, in diabetes care and research.

When we try to solve a real-world problem, due to the complexity and uncertainty nature of the pr... more When we try to solve a real-world problem, due to the complexity and uncertainty nature of the problem, we first tend to describe it under a stochastic model, based on which we then try to find the solution. Therefore, how to model becomes an important and interesting area of either theoretical or practical research. This special issue of IJOR covers the recent advances in stochastic modeling and its application. The areas of interest include the modeling of logistics and service systems, the theory of queueing and inventory models, risk management and heath care.

Annals of Operations Research, 2018

We consider an M/G/1 Markovian feedback queue with multi-class customers. We derive functional eq... more We consider an M/G/1 Markovian feedback queue with multi-class customers. We derive functional equations for the stationary distribution of the queue size and the total response time. A system of linear equations is also derived for the moments of the queue size and the total response time distributions. The mean and the variance of the queue size and the total response time can be computed by solving the system of linear equations. By using the Markovian feedback queue with multi-class customers, we also investigate the M/PH/1 weighted round-robin queue. Numerical examples are given to show that moments of the queue sizes and of the total response times can be easily computed for the weighted round-robin queue. As the service quantum shrinks to zero, the moments of the queue sizes and the total response times converge to some limits which should be the moments of the corresponding discriminatory processor sharing queue.