• Proceedings of the Korea Water Resources Association Conference
• /
• 2022.05a
• /
• pp.166-166
• /
• 2022

본 연구의 목적은 고전적 순간단위도 모형 중의 하나인 Nash 모형의 매개변수와 하천망의 동적 Fractal 차원 사이의 관계를 체계적으로 분석하여 해당 매개변수의 수문학적 의미를 추론해 보는 것이다. Nash 모형의 경우, GIUH 이론과의 결합을 통하여 Horton 비를 기반으로 한 두 매개변수의 지형학적 추정 방법이 일찍부터 제안되어 왔다 (Rosso, 1984; Bhunya, 2008). 특히 Liu(1992)는 2차원 자유 Euclidean 공간 내에서 percolation cluster 모형의 응집구조와 유역의 배수구조 사이의 비교를 통하여 하천망의 Fractal 차원을 정적 Fractal 차원과 동적 Fractal 차원으로 구분하고 양자의 수문학적 의미에 대하여 강조한 바 있다. 본 연구에서는 문헌 조사 (Morisawa, 1962; Marani et al., 1991; Rosso et al., 1991)를 통하여 수집한 비교적 신뢰성 있는 국외 하천망들에 관한 정보를 기반으로 Nash 모형의 매개변수와 하천망의 동적 Fractal 차원 사이의 관계를 분석해 보았다. 주요한 결과로서 Nash 모형의 형상 매개변수와 하천망의 Fractal 차원 사이에는 밀접한 상관관계가 존재함을 알 수 있었으며 이를 통하여 하천망의 Fractal 차원을 이용하여 해당 매개변수를 직접 추정할 수 있는 관계식을 제시할 수 있을 것으로 판단된다. 또한 분광 차원과 Nash 모형의 첨두 좌표 사이의 관계를 통하여 겉보기에서로 다른 유역들 사이에 존재할 수 있는 수문학적 상사성을 평가할 수 있는 기준의 수립 역시 본 연구과정을 통하여 제시할 수 있으로 판단된다. 후속 연구로서 국내외 다수 유역들에 대한 지형분석을 통하여 본 연구에서 얻은 결과의 보편성을 검정하고 수문학적 자료들에 대한 검증을 통하여 Nash 모형을 기반으로 한 다양한 수문학적 모형들의 개선 방안을 제시해 보고자 한다.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.54 no.2
• /
• pp.97-106
• /
• 2005

This paper presents a method for evaluating the nash equilibrium of the Cournot model for N-Gencos in wholesale electricity market. In wholesale electricity market, the strategies of N-Gencos can be applied to the game model under the conditions, which the Gencos determine their strategies to maximize their benefit. Generally, the Lemke algorithm has known as the approach to evaluate the mixed nash equilibrium in the only two-player game model. In this paper, we have developed the necessary condition for obtaining the mixed nash equilibrium of N-player by using the Lemke algorithms. However, it is difficult to find the mixed nash equilibrium of two more players by using the analytic method since those have the nonlinear characteristics. To overcome the above problem, we have formulated the object function satisfied with the proposed necessary conditions for N-player nash equilibrium and applied the modified particle swarm optimization (PSO) method to obtain the equilibrium for N-player. To present the effectiveness the proposed necessary condition and the evaluation approach, this paper has shown the results of equilibrium of sample system and the cournot game model for 3-players.

• Genomics & Informatics
• /
• v.21 no.4
• /
• pp.45.1-45.11
• /
• 2023

Nonalcoholic fatty liver disease (NAFLD) is a common type of chronic liver disease, with severity levels ranging from nonalcoholic fatty liver to nonalcoholic steatohepatitis (NASH). The extent of liver fibrosis indicates the severity of NASH and the risk of liver cancer. However, the mechanism underlying NASH development, which is important for early screening and intervention, remains unclear. Weighted gene co-expression network analysis (WGCNA) is a useful method for identifying hub genes and screening specific targets for diseases. In this study, we utilized an mRNA dataset of the liver tissues of patients with NASH and conducted WGCNA for various stages of liver fibrosis. Subsequently, we employed two additional mRNA datasets for validation purposes. Gene set enrichment analysis (GSEA) was conducted to analyze gene function enrichment. Through WGCNA and subsequent analyses, complemented by validation using two additional datasets, we identified five genes (BICC1, C7, EFEMP1, LUM, and STMN2) as hub genes. GSEA analysis indicated that gene sets associated with liver metabolism and cholesterol homeostasis were uniformly downregulated. BICC1, C7, EFEMP1, LUM, and STMN2 were identified as hub genes of NASH, and were all related to liver metabolism, NAFLD, NASH, and related diseases. These hub genes might serve as potential targets for the early screening and treatment of NASH.

• Journal of Korea Multimedia Society
• /
• v.11 no.3
• /
• pp.353-363
• /
• 2008

A multi-agent system has a longer learning period and larger state-spaces than a sin91e agent system. In this paper, we suggest a new method to reduce the learning time of Nash Q-learning in a multi-agent environment. We apply Macro-actions to Nash Q-learning to improve the teaming speed. In the Nash Q-teaming scheme, when agents select actions, rewards are accumulated like Macro-actions. In the experiments, we compare Nash Q-learning using Macro-actions with general Nash Q-learning. First, we observed how many times the agents achieve their goals. The results of this experiment show that agents using Nash Q-learning and 4 Macro-actions have 9.46% better performance than Nash Q-learning using only 4 primitive actions. Second, when agents use Macro-actions, Q-values are accumulated 2.6 times more. Finally, agents using Macro-actions select less actions about 44%. As a result, agents select fewer actions and Macro-actions improve the Q-value's update. It the agents' learning speeds improve.

• Journal of the Chungcheong Mathematical Society
• /
• v.13 no.1
• /
• pp.13-20
• /
• 2000

The purpose of this paper is to give a new existence theorem of a generalized weight Nash equilibrium for generalized multiobjective games by using the quasi-variational inequality due to Yuan.

• Bulletin of the Korean Mathematical Society
• /
• v.40 no.2
• /
• pp.289-300
• /
• 2003

We prove a simplified version of the Nash-Moser implicit function theorem in weighted Banach spaces. We relax the conditions so that the linearized equation has an approximate inverse in different weighted Banach spaces in each recurrence step.

• Journal of the Chungcheong Mathematical Society
• /
• v.24 no.2
• /
• pp.213-219
• /
• 2011

In this paper, we will prove an equilibrium existence theorem of a non-compact acyclic strategic game with affine constraint correspondences which is comparable with equilibrium existence theorems due to Debreu, Nash, Kim-Kum, and Lu in several aspects.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.5 no.3
• /
• pp.542-559
• /
• 2011

Most game-theoretic works of Aloha have emphasized investigating Nash equilibria according to the system state represented by the number of network users and their decisions. In contrast, we focus on the possible change of nodes' utility state represented by delay constraint and decreasing utility over time. These foregone changes of nodes' state are more likely to instigate selfish behaviors in networking environments. For such environment, in this paper, we propose a repeated Bayesian slotted Aloha game model to analyze the selfish behavior of impatient users. We prove the existence of Nash equilibrium mathematically and empirically. The proposed model enables any type of transmission probability sequence to achieve Nash equilibrium without degrading its optimal throughput. Those Nash equilibria can be used as a solution concept to thwart the selfish behaviors of nodes and ensure the system stability.

• Journal of Korea Water Resources Association
• /
• v.30 no.2
• /
• pp.97-106
• /
• 1997

Parameters of the Nash model were analyzed using similarity concepts for the hydrogeomorphologic and the time response characteristics, then the application of parameter estimation was performed for a basin where no data are available. The self-similarity was investigated to evaluate the similarity of hydrogeomorphologic characteristics and to derive a equation for the time of concentration. The relation between model parameters and time characteristics such as travel and lag time, were developed to obtain their properties of similarity. There were remarkable results about the assessment for basin similarity and the application to an ungaged basin in Wi stream basin.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.23 no.2
• /
• pp.182-189
• /
• 2009

Nash equilibrium is usually used to investigate a generator's strategic bidding in electricity markets. Some literatures show that the transmission constraints may induce no pure strategy equilibrium and make it hard to find the equilibrium. Using an analytical approach to find a mixed strategy Nash equilibrium in electricity market with transmission constraints, we analyze the influence of transmission capacity on the mixed strategy Nash equilibrium. Finally, a simple numerical example is provided to support the claims of this paper.