• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.3A
• /
• pp.217-224
• /
• 2010

In this paper, we propose a hard handover algorithm for a base station's self-optimization, one of the automatic operational technologies for the 3GPP LTE systems. The proposed algorithm simultaneously considers a mixed target sell selection method for optimal selection and a multiple parameter based active hysteresis method with the received signal strength from adjacent cells and the cell load information of the candidate target cells from information exchanges between eNBs through X2 interface. The active hysteresis method chooses optimal handover hysteresis value considering the costs of the various environmental parameters effect to handover performance. The algorithm works on the optimal target cell and the hysteresis value selections for a base station's automatic operational optimization of the LTE system with the gathered informaton effects to the handover performance. The simulation results show distinguished handover performances in terms of the most important performance indexes of handover, handover failure rate and load balancing.

• Journal of Korea Port Economic Association
• /
• v.32 no.3
• /
• pp.21-33
• /
• 2016

This paper examines the effect of strategic trade policy on port ownership structures (nationalization or privatization) when two firms compete with each other in reciprocal markets. Furthermore, we analyze firms profits, port charges, ports profits and social welfare when ports are privatized or nationalized under tariff regime and under free trade regime respectively. Thus, we find that (i) under tariff regime, port nationalization is a dominant strategy regardless of transport costs. (ii) the effect of high port charges brings higher port profits than the effect of high trade volume. (iii) irrespective of trade regime, when transport cost is relatively low, port nationalization increases social welfare, while two government prefer free trade agreement to tariff regime when transport cost is sufficiently high regardless of port ownership structures.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.17 no.3
• /
• pp.29-45
• /
• 2017

Ad hoc sensor network is characterized by decentralized structure and ad hoc deployment. Sensor networks have all basic features of ad hoc network except different degrees such as lower mobility and more stringent energy requirements. Existing protocols provide different tradeoffs among some desirable characteristics such as fault tolerance, distributed computation, robustness, scalability and reliability. wireless protocols suggested so far are very limited, generally focusing on communication to a single base station or on aggregating sensor data. The main reason having such restrictions is due to maximum lifetime to maintain network activities. The network lifetime is an important design metric in ad hoc networks. Since every node does a router role, it is not possible for other nodes to communicate with each other if some nodes do not work due to energy lack. In this paper, we suggest an experimental ad-hoc on-demand distance vector routing protocol to optimize the communication of energy of the network nodes.The load distribution avoids the choice of exhausted nodes at the route selection phase, thus balances the use of energy among nodes and maximizing the network lifetime. In transmission control phase, there is a balance between the choice of a high transmission power that lead to increase in the range of signal transmission thus reducing the number of hops and lower power levels that reduces the interference on the expense of network connectivity.

• Journal of the Korea Society for Simulation
• /
• v.20 no.4
• /
• pp.31-40
• /
• 2011

Sensor nodes are easily exposed to malicious attackers by physical attacks. The attacker can generate various attacks using compromised nodes in a sensor network. The false report generating application layers injects the network by the compromised node. If a base station has the injected false report, a false alarm also occurs and unnecessary energy of the node is used. In order to defend the attack, a statistical en-route filtering method is proposed to filter the false report that goes to the base station as soon as possible. A path renewal method, which improves the method, is proposed to maintain a detection ability of the statistical en-route filtering method and to consume balanced energy of the node. In this paper, we proposed the secure path cycle method to consume effective energy for a path renewal. To select the secure path cycle, the base station determines through hop counts and the quantity of report transmission by an evaluation function. In addition, three methods, which are statistical en-route filter, path selection method, and path renewal method, are evaluated with our proposed method for efficient energy use. Therefore, the proposed method keeps the secure path and makes the efficiency of energy consumption high.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2005.11a
• /
• pp.191-194
• /
• 2005

본 논문은 최적 탐색 알고리즘인 유전자 알고리즘을 이용하여 다항식 뉴럴네트워크(Polynomial Neural Networks : PNN)의 최적 설계가 그 목적이다. 기존의 다항식 뉴럴네트워크는 확장된 GMDH(Group Method of Data Handling) 방법에 기반을 두며, 네트워크의 성장과정을 통하여 각 층의 다항식뉴런(혹은 노드)에서 고정된 (설계자에 의해 미리 선택된) 노드 입력들의 수뿐만 아니라 다항식 차수(1차, 2차, 그리고 수정된 2차식)를 이용하였다. 더구나, 그 방법은 학습을 통해 생성된 PNN이 최적 네트워크 구조를 가진다는 것을 보증하지 못한다. 그러나, 제안된 GA-based PW 모델은 다음의 파라미터들- 즉 입력변수의 수, 입력변수, 및 다항식 차수-을 유전자 알고리즘을 이용하여 선택 동조함으로써 그 구조를 구조적으로 더 최적화된 네트워크가 되도록 하고, 기존의 PNN보다 훨씬 더 유연하고, 선호된 뉴럴 네트워크가 되도록 한다. 하중계수를 가진 합성성능지수가 그 모델의 근사화 및 일반화(예측) 능력 사이의 상호 균형을 얻기 위해 제안된다. GA-based PNN의 성능을 평가하기 위해 그 모델은 가스 터빈발전소의 NOx 배출 공정 데이터로 실험된다. 비교해석은 제안된 GA-based PNN이 앞서 나타난 다른 지능모델보다 더 우수한 예측능력뿐만 아니라 높은 정확성을 가진 모델임을 보인다.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.13 no.5
• /
• pp.163-171
• /
• 2013

This paper proposes an algorithm that seeks the optimal solution for an assignment problem through a simplified process. Generally it is Hungarian algorithm that is prevalently used to solve a given assignment problem. The proposed algorithm reduces 4 steps Hungarian algorithm into 2 steps. Firstly, the algorithm selects the minimum cost from a matrix and deletes the rest of the rows and columns. Secondly, it improves on the solution through reassignment process. For 27 balanced assignment problems and 7 unbalanced problems, the proposed algorithm has successfully yielded the optimal solution, which Genetic algorithm has failed. This algorithm is thus found to be an appropriate replacement of Hungarian algorithm.

• Journal of Nutrition and Health
• /
• v.53 no.4
• /
• pp.431-444
• /
• 2020

Purpose: The purposes of this study were to understand the health interest of consumers in the United States and Japan and thus understand the motivation of food choices, in order to provide basic data on the country's strategy based on healthy and correct food choices in the future. Methods: A customer survey was conducted in 2019 from October 18 to 31, and it targeted 115 American and 120 Japanese local consumers between the ages of 20- to 64-years-old. Eight questions were formed using General Health Interest. Based on food choice motivation, 27 questions were reconstructed and asked about demographic information. All data were analyzed by SPSS Statistics (ver. 25). Results: Health consciousness was categorized into 2 types: nutrition-seeking type and preference-seeking type. Based on these 2 factors, customers were grouped into 3 clusters: healthy dietary life-seeking group, nutrition balance-seeking group and health indifference group. Food choice motivation was categorized into 4 types: health, efficiency, value, and mood. All 3 groups showed a high tendency for efficiency in common. The results show that consumers want higher satisfaction with their time and money invested in food consumption. It is believed that the focus and investment of market segmentation strategy should be focused on product development, especially for American and Japanese consumers who are interested in health. Conclusion: The results of this study reflect consumer needs that can assist in the selection of healthy and correct foods in the future.

• Food Science and Preservation
• /
• v.17 no.3
• /
• pp.418-424
• /
• 2010

Although the wine industry continues to grow, little empirical research on consumer preferences has been conducted. Thus, our objective was to analyze consumer views on wine attributes. A choice experiment (CE) was designed to detect a marginal willingness to pay for particular characteristics of wine (balance, flavor, color, clarity, and value-for-money). A questionnaire was administered and 286 responses were received. A multinomial logit model was estimated using the maximum likelihood method. The results indicated that balance, flavor, color, clarity, and price were all important to consumers. The CE data revealed that estimates of marginal willingness to pay were 31,899 won/bottle for balance, 23,088 won/bottle for flavor, 3,230 won/bottle for color, and 25,936 won/bottle for clarity. The balance of a wine was most important, and the flavor, clarity, and color were also significant. The results of this work will be of assistance in promoting the domestic wine industry.

• Journal of Science Education
• /
• v.37 no.1
• /
• pp.23-39
• /
• 2013

Science teachers' perception on their preparation program can help in conceptualizing how science teachers could be prepared. Based on this premise, this study aims to investigate preservice and inservice science teachers' perception on their teacher preparation programs with a focus on the coherence and balance of program. For this purpose, 20 preservice and 39 inservice science teachers were participated. Selection form and open-ended form questionnaires were developed to survey science teachers' perception on their program. The results of study are as follows: Firstly, participating preservice and inservice science teachers perceived the coherence of their program as moderate. The most and least coherent category of program was 'planning & preparation' and 'professional responsibilities' respectively. Inservice teachers perceived the program less coherent than preservice teachers in all four categories. Secondly, participating preservice and inservice science teachers perceived that practical elements were deficient compare to theoretical elements in light of balance of the program. Lastly, participating preservice and inservice science teachers perceived that current science teacher preparation program was biased to test-driven curriculum, and four domains of the program (subject matter knowledge, pedagogical content knowledge, general pedagogical knowledge, and teaching practicum) need to be more strongly connected to secondary school context. Alternative ways to be more coherent and balanced science teacher preparation program were also discussed based on the research.

• Journal of Technology Innovation
• /
• v.20 no.1
• /
• pp.17-43
• /
• 2012

Alliance formation has been recognized as an important strategy for firms who seek to survive through acquisition of sustainable competitive advantages. Specifically in high-tech industries, firms may consider formation of strategic alliances in order to access valuable external knowledge. These firms tend to be situated in a dilemma that they should choose between exploration and exploitation, which are two types of strategic choices suggested by March (1991). Working out the dilemma has been extensively discussed in the area of strategy or organization learning. Recently, however, an increasing number of studies have stressed on a balance between exploration and exploitation. Regarded as 'ambidextrous organizations' (Lavie and Rosenkopf, 2006), these firms that simultaneously pursue exploration and exploitation have emerged in high-tech industries, and many studies have provided evidence of positive association between organizational ambidexterity and firm performance. In the strategic alliance research, accordingly, scholars began to pay attention to the balanced choice between exploration-and exploitation-oriented alliances. Given these backgrounds, this study examines the relationship between alliance ambidexterity and firm performance. While previous research approached alliance ambidexterity mainly from the number of alliances, our study suggests ambidexterity in terms of alliance portfolio and alliance partner. Our dataset consists of biotechnology or pharmaceutical firms in the United States, which spans time period between 1990 and 2005. We conduct panel data analysis. The results show the strong link between alliance ambidexterity and firm performance, highlighting the balance between exploration and exploitation when firms make strategic decisions.