• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.5
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• pp.26-32
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• 2008

The performance of an analog winner-take-all(WTA) circuit is affected by the corner error and the offset error. Despite the fact that the corner error can be reduced with large transconductance of the transistor, the offset error caused by device mismatch has not been completely studied. This paper presents the complete offset error analysis, and proposes low offset design guidelines and an offset cancellation scheme. The experimental results show good agreement with the theoretical analysis and the drastic improvement of the offset error.

• Journal of the Korea Institute of Military Science and Technology
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• v.23 no.4
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• pp.337-345
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• 2020

The Weapon-Target Assignment(WTA) problem can be formulated as an optimization problem that minimize the threat of targets. Existing methods consider the trade-off between optimality and execution time to meet the various mission objectives. We propose a multi-agent reinforcement learning algorithm for WTA based on mean field game to solve the problem in real-time with nearly optimal accuracy. Mean field game is a recent method introduced to relieve the curse of dimensionality in multi-agent learning algorithm. In addition, previous reinforcement learning models for WTA generally do not consider weapon interference, which may be critical in real world operations. Therefore, we modify the reward function to discourage the crossing of weapon trajectories. The feasibility of the proposed method was verified through simulation of a WTA problem with multiple targets in realtime and the proposed algorithm can assign the weapons to all targets without crossing trajectories of weapons.

• Korean Journal of Organic Agriculture
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• v.25 no.2
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• pp.257-277
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• 2017

This study was conducted to suggest policy implications of providing public function of organic farming. Define the difficulties of rice farmers to provide public utility of organic farming. We estimated the amount of the farmers would like to receive for the practice of organic agriculture using choice experiment methods. By evaluating individual economic values through WTA estimates, its meaningful to grasp farmers preference for organic farming practice and conversion. These results could be used as useful data for future organic agriculture policy. For the expansion of organic farming, it is required to evaluate correct and accurate economic value and reflect this in policy.

• 한국노년학
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• v.29 no.1
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• pp.177-194
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• 2009

Korea government has launched long-term care insurance from 2008. However, one of the most important issues, whether or not providing cash benefit, is still unresolved. In this paper, in order to provide policy guidelines for the long-term care insurance, I attempt to estimate the Willingness-To-Accept (WTA) of the cash subsidy for informal care by using Double Bounded Dichotomous Choice method, a branch of Contingent Valuation Method (CVM). In doing so, I also estimated the determinants of the preference for cash benefit. Data were obtained from face-to-face survey interviews with 300 informal care-givers at three major general hospitals in Seoul, Korea. The questionnaire was constructed with two scenarios (mild/severe symptom). The results from logistic regression analyses and the estimation of WTA indicate that informal care-givers are willing to accept the cash benefit as low as 628 thousands won for mild fragile elderly and 1,072 thousands won for severe fragile elderly. The strength of this paper is that I estimated the WTA of the cash benefit by reflecting the changes in preferences of informal care-givers. The analytic results from the this paper suggest that the cash benefit in long-term care insurance is indispensible in achieving the goal of the long-term care system.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.4
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• pp.260-267
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• 2017

Quantum-inspired Genetic Algorithm (QGA) is a probabilistic search optimization method combined quantum computation and genetic algorithm. In QGA, the chromosomes are encoded by qubits and are updated by quantum rotation gates, which can achieve a genetic search. Asset-based weapon target assignment (WTA) problem can be described as an optimization problem in which the defenders assign the weapons to hostile targets in order to maximize the value of a group of surviving assets threatened by the targets. It has already been proven that the WTA problem is NP-complete. In this study, we propose a QGA and a hybrid-QGA to solve an asset-based WTA problem. In the proposed QGA, a set of probabilistic superposition of qubits are coded and collapsed into a target number. Q-gate updating strategy is also used for search guidance. The hybrid-QGA is generated by incorporating both the random search capability of QGA and the evolution capability of genetic algorithm (GA). To observe the performance of each algorithm, we construct three synthetic WTA problems and check how each algorithm works on them. Simulation results show that all of the algorithm have good quality of solutions. Since the difference among mean resulting value is within 2%, we run the nonparametric pairwise Wilcoxon rank sum test for testing the equality of the means among the results. The Wilcoxon test reveals that GA has better quality than the others. In contrast, the simulation results indicate that hybrid-QGA and QGA is much faster than GA for the production of the same number of generations.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.2
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• pp.221-227
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• 2019

It has long been known that weapon target assignment (WTA) problem is NP-hard. Nonetheless, an exact solution can be found using Brute-Force or branch-and bound method which utilize approximation. Many heuristic algorithms, genetic algorithm particle swarm optimization, etc., have been proposed which provide near-optimal solutions in polynomial time. This paper suggests polynomial time algorithm that can be obtain the optimal solution of WTA problem for the number of total weapons k, the number of weapon types m, and the number of targets n. This algorithm performs k times for O(mn) so the algorithm complexity is O(kmn). The proposed algorithm can be minimize the number of trials than brute-force method and can be obtain the optimal solution.

• Korean Journal of Organic Agriculture
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• v.28 no.4
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• pp.555-577
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• 2020

This study analyzes the management performance and productivity of environmentfriendly farms compared to conventional farms and the trend of changes in price premium rates of environment-friendly agricultural products. And environmentfriendly farms in Jeollanam-do are surveyed for difficulties in management, proper premium rate of environment-friendly agricultural products (WTA), and tasks for promoting sales. According to the analysis results, the management performance and productivity of are low in many items, and the number of items that are on the decline or stagnant in the environment-friendly premium is making it difficult for farmers to manage. According to a farm survey, the most important task is to promote school meals for boosting sales of environment-friendly agricultural products. And 65.5% of the respondents having contract cultivation, nearly half or 41.1% of the respondents said they do not need contract cultivation or want contract cultivation for less than one year, which means that the current contract does not meet the needs of farmers. Finally, the environment-friendly premium rate based on consumer prices is generally lower than the premium rate (WTA) that farmers perceive as appropriate, so it is important to resolve the gap between the actual premium rate and the WTA.

• World Technopolis Review
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• v.1 no.2
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• pp.141-154
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• 2012

• Korean Journal of Organic Agriculture
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• v.28 no.3
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• pp.273-288
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• 2020

The purpose of this study is to estimate farmers' willingness to accept (WTA) of direct payment for increasing public benefit using the contingent valuation method. The double-bounded dichotomous choice and the open-ended question were used to measure WTAs for basic form and optional form, respectively. The results show that WTA for basic form was inversely proportional to the acreage. WTAs were KRW 1,694,001 with 2 ha or less, KRW 1,617,789 with over 2 ha~6 ha, and KRW 1,562,977 with over 6 ha. The results also indicate that WTAs for optional form are similar to payments of agricultural environmental conservation program except physical (chemical) control of pests and weed. The results of this study can provide useful information for the establishment of direct payment for increasing public benefit.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.3
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• pp.441-453
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• 2017

In this paper, a new type of weapon-target assignment(WTA) problem has been suggested that reflects realistic constraints for sharing target with other weapons and shooting double rapid fire. To utilize in rapidly changing actual battle field, the computation time is of great importance. Several metaheuristic methods such as Simulated Annealing, Tabu Search, Genetic Algorithm, Ant Colony Optimization, and Particle Swarm Optimization have been applied to the real-time WTA in order to find a near optimal solution. A case study with a large number of targets in consideration of the practical cases has been analyzed by the objective value of each algorithm.