• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권9호
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• pp.4188-4206
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• 2016

Power control is widely used to reduce co-channel interference in wireless networks and guarantee the signal-to-interference plus noise ratio (SINR) of ongoing connections. This technique is also effective for wireless body area networks (WBANs). Although achieving satisfactory SINR is important for WBAN users, they may not be willing to achieve it at arbitrarily high power levels since power is a scarce resource in WBANs. Besides, for WBANs with different purposes, the QoS requirements and concern about the power consumption may be different. This motivates us to formulate the power control problem using the concepts from microeconomics and game theory. In this paper, the QoS objective is viewed as a utility function, which represents the degree of user satisfaction, while the power consumption is viewed as a cost function. The power control problem consequently becomes a non-cooperative multiplayer game, in which each player tries to maximize its net utility, i.e., the utility minus the cost. Within this framework, we investigate the Nash equilibrium existence and uniqueness in the game and derive the best response solution to reach the Nash equilibrium. To obtain the optimal transmission power in a distributed way, we further propose a utility-based and QoS-aware power control algorithm (UQoS-PCA). Tunable cost coefficient in UQoS-PCA enables this scheme to be flexible to satisfy diverse service requirements. Simulation results show the convergence and effectiveness of the proposed scheme as well as improvements over existing algorithm.

• 한국병원경영학회지
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• 제18권2호
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• pp.57-80
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• 2013

The purpose of this study is to examine the information search behavior of medical consumers visiting a hospital, and investigate the consumption values of medical consumers, classified according to the information search behavior, and characteristics of online health and disease information. This study also tried to identify the factors affecting medical consumers classified according to information search behavior, and gain an extensive understanding of medical consumers'consumption values and online information use. The analysis results of this study are as follows: First, the consumption values of medical consumers were classified into a total of 7 factors, i.e. future-positive value, family-oriented value, sustainablehealth value, rational-progressive value, social-cooperative value, socialachiever value and hedonistic-individual value. Next, the characteristics of medical consumers'online information search behavior were classified into three types of consumer groups, i.e. the limited information-oriented consumer group, the practical information-oriented consumer group and the passionate information-oriented consumer group. Second, the analysis of the differences among the three groups classified according to the characteristics of the information search behavior in terms of consumption values, use of online information sources, utility and the intention to reuse online information showed that all the differences were statistically significant. The passionate information-oriented consumer group showed the highest scores in the sustainable-health value, the social-achiever value and the hedonisticindividual value. Third, the factors affecting medical consumers, classified into three groups according to the characteristics of the information search behavior, were found to be socio-demographic variables like consumers' age and occupation, consumers'consumption values, use of online information sources, and utility of online information. This study tried to understand what values medical consumers have according to the differences in the information search behavior by examining the consumption values of medical consumers according to the information search behavior. The significance of this study lies in the fact that consumption values are instrumental in understanding medical consumers by identifying the fundamental motives and desires of consumers' behavior.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권12호
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• pp.3071-3095
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• 2013

Configuring optimization of wireless sensor networks, which can improve the network performance such as utilization efficiency and network lifetime with minimal energy, has received considerable attention in recent years. In this paper, a cross layer optimal approach is proposed for multi-source linear network and grid network under Rayleigh block-fading channels, which not only achieves an optimal utility but also guarantees the end-to-end reliability. Specifically, in this paper, we first strictly present the optimization method for optimal nodal number $N^*$, nodal placement $d^*$ and nodal transmission structure $p^*$ under constraints of minimum total energy consumption and minimum unit data transmitting energy consumption. Then, based on the facts that nodal energy consumption is higher for those nodes near the sink and those nodes far from the sink may have remaining energy, a cross layer optimal design is proposed to achieve balanced network energy consumption. The design adopts lower reliability requirement and shorter transmission distance for nodes near the sink, and adopts higher reliability requirement and farther transmission distance for nodes far from the sink, the solvability conditions is given as well. In the end, both the theoretical analysis and experimental results for performance evaluation show that the optimal design indeed can improve the network lifetime by 20-50%, network utility by 20% and guarantee desire level of reliability.

• 한국경영과학회지
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• 제10권1호
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• pp.31-40
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• 1985

When an economy has institutional price constraints the relationship between market prices and shadow prices is not yet fully investigated. A pure consumption economy is considered where market prices guide the consumption behavior and shadow prices measure the social value of resources. In this case we show that if the utility function is additively separable there exists a complementarity relation between the difference of the market price and the shadow price and the difference of the market price and the regulated upper (or lower) bound.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2000년도 학술대회논문집
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• pp.235-240
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• 2000

This paper presents the reasonable method for electric power management through efficient use of electricity. With a rapid of national economics and living standard, electrical energy consumption markedly increased. Especially it is increased electrical energy consumption in commercial buildings and thus an energy conservation through efficient use of electricity became more important.

• 충청수학회지
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• 제32권2호
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• pp.215-224
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• 2019

We investigate the optimal consumption and investment decision problem of an agent whose time preference is time-inconsistent. Specifically, for a time-separable utility function, the agent's subjective discount factor is supposed to be changed randomly in the future. We provide closed-form solutions in the presence of income process. The method can be extended into the case with a stochastic income process.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1997년도 전력전자학술대회 논문집
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• pp.386-392
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• 1997

Recently, according to developing industry and life style, power consumption have been increased year after year. Currently these much power demand from power consumer is weakening the allowable power reserve margin in summer. As one of the remedies about this problem, the small scale utility interactive photovoltaic system(UIPVS) is considered for auxiliary power source. For this system one of problems to be solved technically, system operating power factor. Generally in case of small scale system, system is operated in unity power factor. But this unity power factor operating mode decrease power factor viewed from utility because UIPVS supply active power to utility. Therefore this paper propose UIPVS with power factor correcting function and this system is analyzed.

• Journal of information and communication convergence engineering
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• 제21권2호
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• pp.117-129
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• 2023

High-utility itemset mining (HIUM) has emerged as a key data-mining paradigm for object-of-interest identification and recommendation systems that serve as frequent itemset identification tools, product or service recommendation systems, etc. Recently, it has gained widespread attention owing to its increasing role in business intelligence, top-N recommendation, and other enterprise solutions. Despite the increasing significance and the inability to provide swift and more accurate predictions, most at-hand solutions, including frequent itemset mining, HUIM, and high average- and fast high-utility itemset mining, are limited to coping with real-time enterprise demands. Moreover, complex computations and high memory exhaustion limit their scalability as enterprise solutions. To address these limitations, this study proposes a model to extract high-utility frequent closed itemsets based on an improved cumulative summary list structure (CSLFC-HUIM) to reduce an optimal set of candidate items in the search space. Moreover, it employs the lift score as the minimum threshold, called the cumulative utility threshold, to prune the search space optimal set of itemsets in a nested-list structure that improves computational time, costs, and memory exhaustion. Simulations over different datasets revealed that the proposed CSLFC-HUIM model outperforms other existing methods, such as closed- and frequent closed-HUIM variants, in terms of execution time and memory consumption, making it suitable for different mined items and allied intelligence of business goals.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권7호
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• pp.3566-3582
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• 2019

In intelligent warehouse picking system, the allocation of tasks has an important influence on the efficiency of the whole system because of the large number of robots and orders. The paper proposes a method to solve the task allocation problem that multi-robot task allocation problem is transformed into transportation problem to find a collision-free task allocation scheme and then improve the capability of task processing. The task time window and the power consumption of multi-robot (driving distance) are regarded as the utility function and the maximized utility function is the objective function. Then an integer programming formulation is constructed considering the number of task assignment on an agent according to their battery consumption restriction. The problem of task allocation is solved by table working method. Finally, simulation modeling of the methods based on table working method is carried out. Results show that the method has good performance and can improve the efficiency of the task execution.

• 디지털융복합연구
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• 제18권11호
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• pp.81-86
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• 2020

본 연구는 소비 트렌드를 선도하는 80년대 이후 출생한 젊은 층을 중심으로 소비자의 예기된 죄책감이 녹색소비의도에 미치는 영향을 지각된 효과성을 매개효과로 검증하였다. AMOS에 의한 가설점증 결과, 예기된 죄책감은 녹색소비의도와 지각된 효과성에 모두 정(+)의 영향을 미치며, 지각된 효과성은 녹색소비의도에 정(+)의 영향을 미치고, 지각된 효과성은 예기된 죄책감과 녹색소비의도 간에 부분적인 매개역할을 하는 것으로 검증되었다. 본 연구의 결과는 죄책감이라는 친사회적 특징을 지닌 부정적 정서가 녹색소비의도에 미치는 영향을 분석하여 녹색소비를 유도하기 위한 이론적 근거와 정책적 시사점을 제시하였다. 본 연구는 이론적 및 실무적으로 기여하는 바가 있음에도 불구하고 일부 한계점이 존재한다.