• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.4
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• pp.477-483
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• 2015

The k-Winners-Take-All (kWTA) is an operation to find the largest k (>1) inputs among N inputs. Parallel search algorithm of kWTA for digital inputs is not invented yet, so most of digital kWTA architectures have O(N) time complexity. A parallel search algorithm for digital kWTA operation and the circuits for its VLSI implementation are presented in this paper. The proposed kWTA architecture can compare all inputs simultaneously in parallel. The time complexity of the new architecture is O(logN), so that it is scalable to a large number of digital data. The high-speed kWTA operation and its O(logN) dependency of the new architecture are verified by simulations. It takes 290 ns in searching for 5 winners among 1024 of 32 bit data, which is more than thousands of times faster than existing digital kWTA circuits, as well as existing analog kWTA circuits.

• Environmental and Resource Economics Review
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• v.17 no.3
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• pp.135-166
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• 2008

This paper reports the empirical results of comparing the willingness to pay(WTP) for health risk reductions and the willingness to accept(WTA) for risk increases using experimental market methods in the first time in Korea. Health risks were defined as probabilities of premature death from exposure to one of As, Pb, and THM in tap water. A total of six experimental markets with 15 participants in each experiments were held using 20 repetitive Vickrey second-price sealed-bid auctions. To compare the effects of market experiences, trading a marketed good, candy bar, was introduced before the trading the non-marketed good, drinking water risks. Moreover, an objective risk information was provided after the first 10 trials to incorporate learning processes. Regardless of marketed or non-marketed goods, the mean of WTA exceeded the mean of WTP at the first auction trial. As experimental trials proceeded, the disparity between WTA and WTP for marketed goods disappeared. However results for non-marketed goods were rather mixed to the extent that WTA for health risks from As (relatively high risk leves) were significantly larger than WTP, while there were no significant difference between WTA and WTP for health risks fro Pb and THM (relatively low risk levels). On the other hand, participants seemed to respond in a 'rational' manner to the objective risk information provided, with positive learning effects of market-like experience(especially in the WTA experiments).

• Proceedings of the Korea Information Processing Society Conference
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• 2001.04a
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• pp.561-564
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• 2001

본 논문은 무선 에플리케이션 프로토콜 Specification에서 제시하고 있는 WTA(Wireless Telephony Application) 를 기초로 네트워크에서 발생한 실시간 Event를 처리할 수 있는 모바일 클라이언트 및 WTA서버에 대한 설계와 구현에 대해서 기술한다. 또한 네트워크 이벤트 및 사용자가 발생시킨 이벤트를 디바이스에 독립적으로 처리할 수 있는 WTA 라이브러리와 필요한 컨텐츠를 실시간으로 브라우징하기 위한 Repository 에 대해 기술한다. 전체적인 WTA 환경 구조는 크게 2개의 물리적 구조인 Mobile Client와 WTA Server로 구현되어있다. Mobile Client의 내부 모듈은 표준 WAE 사용자 에이전트(Standard WAE User Agent)의 확장인 WTA 사용자 에이전트 모듈(WTA User-Agent Module), 필요한 resource를 서버로 요청하고 저장하는 채널 인스톨 모듈(Channel Install Module), network로부터 발생한 Event를 처리하는 이벤트 핸들러 모듈(Event Handler Module), mobile network 기능들(e.g. setting up calls)과 device specific feature(e.g. manipulating the phonebook)를 다루는 WTA 스크립트 라이브러리(WTA Script Library), Phonebook 엑세스 모듈(Phonebook Access Module), 실시간으로 즉각 이벤트에 반응하기 위한 Repository로 구성되어있고, WTA Server는 Client가 요청한 Content(services)를 전달 해 주는 컨텐트 전달 모듈(Content Deliver Module)과 서버 Phonebook 엑세스 모들(Server Phonebook Access Module)로 구성되어 있다.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.5
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• pp.540-548
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• 2012

The Weapon Target Allocation(WTA) problem is the NP-Complete problem. The WTA problem is that the threatful air targets are assigned by weapon of allies for killing the targets. A good solution of NP-complete problem is heuristic algorithms. Genetic algorithms are commonly used heuristic for global optimization, and it is good solution on the diverse problem domain. But there has been very little research done on the generation of their initial population. The initialization of population is one of the GA step, and it decide to initial value of individuals. In this paper, we propose to the population initialization method to improve a Genetic Algorithm. When it initializes population, the proposed algorithm reflects the characteristics of the WTA problem domain, and inherits the dominant gene. In addition, the search space widely spread in the problem space to find efficiently the good quality solution. In this paper, the proposed algorithm to verify performance examine that an analysis of various properties and the experimental results by analyzing the performance compare to other algorithms. The proposed algorithm compared to the other initialization methods and a general genetic algorithm. As a result, the proposed algorithm showed better performance in WTA problem than the other algorithms. In particular, the proposed algorithm is a good way to apply to the variety of situation WTA problem domain, because the proposed algorithm can be applied flexibly to WTA problem by the adjustment of RMI.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.12
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• pp.856-864
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• 2019

The weapon-target assignment (WTA) problem is a matter of effectively allocating weapons to a number of threats. The WTA in a rapidly changing dynamic environment of engagement must take into account both of properties of the threat and the weapon and the effect of the previous decision. We propose a method of applying the Greedy Randomized Adaptive Search Procedure (GRASP) algorithm, a kind of meta-heuristic method, to derive optimal solution for a dynamic WTA problem. Firstly, we define a dynamic WTA problem and formulate a mathematical model for applying the algorithm. For the purpose of the assignment strategy, the objective function is defined and time-varying constraints are considered. The dynamic WTA problem is then solved by applying the GRASP algorithm. The optimal solution characteristics of the formalized dynamic WTA problem are analyzed through the simulation, and the algorithm performance is verified via the Monte-Carlo simulation.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1386-1389
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• 2002

We consider interleaved buck converters using a switching rule based on Winner-Take-All (ab. WTA) nonlinearity. We clarify that this system exhibits various bifurcation phenomena. We also show that the switching phase of each converter is controlled by the WTA. Using a simple test circuit, ripple reduction and typical phenomena are verified in the laboratory.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.535-537
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• 2001

WAP(Wireless Telephony Application)을 이용한 무선 인터넷 서비스는 한정된 장소와 PC라는 제한된 장비를 사용하여 인터넷에 접속하는 것을 모바일로 이동시켜 시간과 공간, 장비의 제약을 극복한 기술이다. 최근 무선 인터넷 시장은 급속히 발전하고 있으며 컨텐츠와 모바일 서비스에 대한 사용자들의 다양한 요구가 증가되고 있는 추세이다. 이에 따라 무선 이동 통신 사업자들은 기존 전화 서비스와 무선 인터넷의 통합을 추진하고 있다. 본 논문은 WAP 표준에 준거한 WTA(Wireless Telephony Application)서버의 설계와 구현에 대하여 기술한다.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.2
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• pp.177-183
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• 2015

A high speed VLSI digital Winner-Take-All (WTA) circuit called simultaneous digital WTA (SDWTA) circuit is presented in this paper. A minimized comparison-cell (w-cell) is developed to reduce the size and to achieve high-speed. The w-cell which is suitable for VLSI implementation consists of only four transistors. With a minimized comparison-cell structure SDWTA can compare thousands of data simultaneously. SDWTA is scalable with O(mlog n) time-complexity for n of m-bit data. According to simulations, it takes 16.5 ns with $1.2V-0.13{\mu}m$ process technology in finding a winner among 1024 of 16-bit data.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.8
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• pp.763-771
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• 2011

An optimization procedure for the design of a ventilation axial-flow fan is presented in this paper. Flow analyses of the preliminary fan are performed by solving three-dimensional Reynolds-averaged Navier-Stokes equations via a finite-volume solver with the shear-stress transport turbulence model as a turbulence closure. Three variables, the hub-to-tip ratio and the stagger angles at the mid and tip spans, are selected for the optimization. The Latin-hypercube sampling method as a design-of-experiments technique is used to generate twenty-five design points within the design space. and the weighted average surrogate models, WTA1, WTA2, and WTA3, are applied for find optimal designs. The results show that the efficiency is considerably enhanced.

• Environmental Analysis Health and Toxicology
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• v.29
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• pp.13.1-13.11
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• 2014

Objectives This study examined variations in the perceptions of dioxin risk among social groups defined by geographical living location, environmental education, and occupation. Dioxin risk perceptions were analyzed according to values, risk awareness, knowledge, and behavioral preferences. Methods A quasi-experimental survey was designed and conducted on individuals from seven experimental groups in Jeonju city, South Korea, including: people living near incineration facilities; people living far from incineration facilities; governmental experts; non-governmental organization members; office workers in developmental institutes or banks; students who were enrolled in environmental-related classes; and students who were enrolled in business-related classes. Results The results show variations among groups in values, awareness and behavioral preferences. Particular attention should be given to the result that groups with higher connectedness-to-nature values show higher willingness-to-act (WTA) for risk reduction. Result s can be summarized as follows. First, awareness is associated with one's geographical setting. Second, values and WTA behaviors are related to one's environmental-related education and occupation. Third, values are significantly related to WTA behaviors. Conclusions Different cultures, in terms of values or worldview, among groups influence their perceptions of dioxin risk and choices of risk reduction behaviors. It is important to consider values in communicating complicated long-term risk management involving public participation. Further research should be continuously conducted on the effects of multiple dimensions of values on one's WTA for risk reduction behaviors.