• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권12호
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• pp.3133-3151
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• 2012

The optimal price strategy selection of two bounded rational cognitive mobile virtual network operators (MVNOs) in a duopoly spectrum sharing market is investigated. The bounded rational operators dynamically compete to sell the leased spectrum to secondary users in order to maximize their profits. Meanwhile, the secondary users' heterogeneous preferences to rate and price are taken into consideration. The evolutionary game theory (EGT) is employed to model the dynamic price strategy selection of the MVNOs taking into account the response of the secondary users. The behavior dynamics and the evolutionary stable strategy (ESS) of the operators are derived via replicated dynamics. Furthermore, a reward and punishment mechanism is developed to optimize the performance of the operators. Numerical results show that the proposed evolutionary algorithm is convergent to the ESS, and the incentive mechanism increases the profits of the operators. It may provide some insight about the optimal price strategy selection for MVNOs in the next generation cognitive wireless networks.

• 동굴
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• 제88호
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• pp.38-44
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• 2008

동굴의 관계적 입지를 파악하기 위하여, 네트워크분석 기법 중 네트워크의 점의 지위 분석을 중심으로 하는 각종 지수를 적용하여 그 효용성을 파악하는데 목적을 두었다. (1)동굴의 연결 강도 및 중앙성에 따른 관계적 입지특성에 관한 고찰, (2)동굴관광지와 주변관광지 또는 다른 동굴관광지 간의 구조적 등위성에 관한 고찰을 하였다. 본 연구에서 고찰한 각종 지수 들은 네트워크상의 동굴의 지위를 파악하는데 매우 유용하여, 주변 관광지와의 관계적 입지특성을 보다 객관적이며 수량적으로 표현가능 함을 밝혔다. 특히, 동굴주변에 다 동굴이 위치하는 경우에는 그들 동굴간의 상호 비교나 구조적 우위성을 파악하는데 매우 유용하다.

• Earthquakes and Structures
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• 제26권2호
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• pp.87-96
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• 2024

This paper proposes a logistic multinomial regression approach to model the spatial cross-correlation of damage probabilities among different damage states in an expanded transportation network. Utilizing Bayesian theory and the multinomial logistic model, we analyze the damage states and probabilities of bridges while incorporating damage correlation. This correlation is considered both between bridges in a network and within each bridge's damage states. The correlation model of damage probabilities is applied to the seismic assessment of a portion of Tehran's transportation network, encompassing 26 bridges. Additionally, we introduce extra daily traffic time (EDTT) as an operational parameter of the transportation network and employ the shortest path algorithm to determine the path between two nodes. Our results demonstrate that incorporating the correlation of damage probabilities reduces the travel time of the selected network. The average decrease in travel time for the correlated case compared to the uncorrelated case, using two selected EDTT models, is 53% and 71%, respectively.

• 한국경제지리학회지
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• 제10권4호
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• pp.355-376
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• 2007

본 연구는 한국경제지리학 성립 50년($1956{\sim}2005$년) 동안 경제지리학 연구 틀의 조류를 시기별 방법론상의 변화 등을 고찰하는 것을 목적으로 한다. 한국경제지리학에 영향을 미친 요인은 한국의 지리학을 위시하여 구미 일본의 경제지리학, 경제 경영학의 기초이론, 지역문제, 문화의 다섯 가지이며, 경제지리학의 시기구분은 1956년부터 1962년까지의 '경제지리학 요람기', $1963{\sim}1970$년대 후기까지의 '경제지리학 정립기', 1980년대 전기부터 1990년대 전기까지의 '경제지리학 도약기', 1990년대 후기 이후의 '경제지리학 전환기'로 구분할 수 있다. 그리고 한국경제지리학의 연구 틀은 '경제지리학 도약기'까지는 지역구조가, 그 이후 '경제지리학 전환기'에는 경제의 공간체계 네트워크론으로 바뀌어졌다. 경제의 공간체계 네트워크론은 세계경제의 공간체계, 국민경제의 공간체계, 지역경제의 공간체계, 기업경제의 공간 네트워크, 정보경제의 공간 네트워크로 구성된다.

• Journal of Communications and Networks
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• 제18권5호
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• pp.784-795
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• 2016

In this paper, we investigate the resource allocation problem in time-varying heterogeneous wireless networks (HetNet) with multi-homing user equipments (UE). The stochastic optimization model is employed to maximize the network utility, which is defined as the difference between the HetNet's throughput and the total energy consumption cost. In harmony with the hierarchical architecture of HetNet, the problem of stochastic optimization of resource allocation is decomposed into two subproblems by the Lyapunov optimization theory, associated with the flow control in transport layer and the power allocation in physical (PHY) layer, respectively. For avoiding the signaling overhead, outdated dynamic information, and scalability issues, the distributed resource allocation method is developed for solving the two subproblems based on the primal-dual decomposition theory. After that, the adaptive resource allocation algorithm is developed to accommodate the timevarying wireless network only according to the current network state information, i.e. the queue state information (QSI) at radio access networks (RAN) and the channel state information (CSI) of RANs-UE links. The tradeoff between network utility and delay is derived, where the increase of delay is approximately linear in V and the increase of network utility is at the speed of 1/V with a control parameter V. Extensive simulations are presented to show the effectiveness of our proposed scheme.

• 한국정보시스템학회지:정보시스템연구
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• 제29권2호
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• pp.131-147
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• 2020

Purpose The purpose of this study is to develop intelligent vehicle parking distribution system based on LoRa network at the circumstance of traffic congestion during cultural festival in a local city. This paper proposes a parking dispatch and distribution system using a Q-learning algorithm to rapidly disperse traffics that increases suddenly because of in-bound traffics from the outside of a city in the real-time base as well as to increase parking probability in a parking lot which is widely located in a city. Design/methodology/approach The system get information on realtime-base from the sensor network of IoT (LoRa network). It will contribute to solve the sudden increase in traffic and parking bottlenecks during local cultural festival. We applied the simulation system with Queuing model to the Yudeung Festival in Jinju, Korea. We proposed a Q-learning algorithm that could change the learning policy by setting the acceptability value of each parking lot as a threshold from the Jinju highway IC (Interchange) to the 7 parking lots. LoRa Network platform supports to browse parking resource information to each vehicle in realtime. The system updates Q-table periodically using Q-learning algorithm as soon as get information from parking lots. The Queuing Theory with Poisson arrival distribution is used to get probability distribution function. The Dijkstra algorithm is used to find the shortest distance. Findings This paper suggest a simulation test to verify the efficiency of Q-learning algorithm at the circumstance of high traffic jam in a city during local festival. As a result of the simulation, the proposed algorithm performed well even when each parking lot was somewhat saturated. When an intelligent learning system such as an O-learning algorithm is applied, it is possible to more effectively distribute the vehicle to a lot with a high parking probability when the vehicle inflow from the outside rapidly increases at a specific time, such as a local city cultural festival.

• 한국도서관정보학회지
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• 제53권1호
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• pp.191-210
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• 2022

Niklas Luhmann은 다른 학문 분야에도 막강한 영향력을 끼치고 있는 사회학자이다. 따라서 Luhmann의 이론이 후속 연구자들에게 어떤 영향력을 끼쳤는지를 검토할 필요가 있다. 이 연구는 Niklas Luhmann의 이론을 연구하는 후속연구자들의 지식 네트워크를 분석하였고, 분석 방법은 서지결합과 동시인용을 사용하였다. 주요 결과는 다음과 같다. 첫째, 서지결합분석을 통해서는 남미·스페인어권, 서유럽·영미권, 동·북유럽 및 기타 어권으로 클러스터가 나뉘었다. 둘째, 서지결합 노드 단위 분석에서는 주로 Luhmann의 핵심 저작을 인용한 경우, Luhmann의 주변 저작들을 인용한 경우로 나뉘었다. 셋째, 동시인용분석을 통해서는 Luhmann의 저작 중 반복적으로 인용되는 핵심 저작군이 있는 것으로 나타났다. 넷째, 동시인용 네트워크의 노드 단위 분석에서는 12개의 핵심 저작이 도출되었고, 핵심 저작들은 주제에 따라 4개의 저작군으로 나타났다.

• 환경영향평가
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• 제19권3호
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• pp.307-314
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• 2010

Brebbia's model has been analyzed to develop the appropriate waterworks management system in Korea, and compared with the conventional models such as EPANET, WaterCad, and InfoWorks. The hydraulic theory of the models was analyzed. Each model's numerical techniques, required parameters, input data and operational methodologies, restrictions, practical applicability and other aspects were investigated. In order to check the validity of Brebbia model, the comparative analysis with EPANET, WaterCAD, and InfoWorks models was performed for linear and nonlinear cases. To find out advantages and disadvantages of each model, the modeling was performed for a simple network and for more complicated A city waterworks system, and the three models applicability was examined. Finally, optimal modeling technique and a model suitable for the use in Korea was suggested, and the problems related to present projects of waterworks management system in Korea were analyzed.

• 한국정보처리학회논문지
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• 제4권1호
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• pp.177-183
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• 1997

비 중심t분포의 누적함수는 두 정규모집단에서 모평균의 동일성 검정에서 검정력 계산 및 모 평균에 대한 표준편차의 비에 대하여 신뢰구간을 계산할 때 요구된다. 본 논문에서는 비중심t분포의 누적함수 계산에 신경망 이론을 적용하였다. 신경망은 다 층 퍼셉트론이며 학습과정은 역전파 학습알고리즘이다. Fisher가 제시한 확률값과 신 경망이론에 의하여 계산한 결과를 비교하였다.

• The Korean Journal of Ecology
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• 제23권2호
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• pp.89-100
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• 2000

On community data. sampled in regular intervals on a long-term basis. artificial neural networks were implemented to extract information on characterizing patterns of community changes. The Adaptive Resonance Theory and Kohonen Network were both utilized in learning benthic macroinvertebrate communities in the Soktae Stream of the Suyong River collected monthly for three years. Initially, by regarding each monthly collection as a separate sample unit, communities were grouped into similar patterns after training with the networks. Subsequently, changes in communities in a sequence of samplings (e.g., two-month, four-month, etc.) were given as input to the networks. After training, it was possible to recognize new data set in line with the sampling procedure. Through the comparative study on benthic macroinvertebrates with these learning processes, patterns of community changes in chironomids diverged while those of the total benthic macro-invertebrates tended to be more stable.