• Journal of Communications and Networks
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• 제17권4호
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• pp.370-383
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• 2015

Effective link quality estimation is a vital issue for reliable routing in wireless networks. This paper studies the performance of expected transmission count (ETX) under different traffic loads. Although ETX shows good performance under light load, its performance gets significantly worse when the traffic load is high. A broadcast packet storm due to new route discoveries severely affects the link ETX values under high traffic load, which makes it difficult to find a good path. This paper presents the design and implementation of a variation of ETX called high load - ETX (HETX), which reduces the impact of route request broadcast packets to link metric values under high load. We also propose a reliable routing protocol using link quality metrics, which is called link quality distance vector (LQDV). We conducted the evaluation of the performance of three metrics - HETX, ETX and minimum hop-count. The simulation results show that HETX improves the average route throughput by up to 25% over ETX under high traffic load. Minimum hop-count has poor performance compared with both HETX and ETX at all of the different traffic loads. Under light load, HETX and ETX show the same performance.

• 전기학회논문지
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• 제61권5호
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• pp.777-781
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• 2012

In this paper, an electrical power simulation program was developed to predict the energy consumption of the electrical railway propulsion system, which considered the actual operating conditions of the electric railway vehicles. The developed program was designed to predictable the energy consumption during a virtual driving in the actual route of the virtual railway vehicles equipped with a propulsion system consisting of power conversion equipments and traction motors. In addition, the accuracy verification of the electrical power simulation program for a propulsion system was performed by using a real power consumption data, which was measured during the driving of the railway vehicles in the Gyeongui Line. In conclusion, the electrical power simulation program for a propulsion system was validated throughout a comparative investigation between the simulated values and the experimental values and the energy consumption characteristics of electric railway vehicles on the existing route or the new route will be possible to predict throughout the virtual simulation considering the driving conditions of the electric railway vehicles.

• Acta Via Serica
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• 제8권1호
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• pp.101-120
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• 2023

In March 1245, Pope Innocent IV authorized three missions to the Mongols, seeking information about this menace from the East and summoning Eastern Christian support against an anticipated Mongol onslaught. Only one of the missions, led by John of Plano Carpini, reached Mongolia-the first-known Western European party to reach East Asia by a land route. Traveling along the Silk Road's new "Grasslands Route," John and his companion Benedict reached the camp of Güyüg Khan, where they witnessed his installation as the Great Khan. Upon their return to the papal court in 1247, they delivered Güyüg's letter demanding the submission of the pope and all the West's princes. John also presented a detailed report on what he and Benedict had learned. A close reading of it reveals a master intelligence operative at work. In addition to presenting an overview of Mongol history and culture, Friar John's report provides detailed information on the Mongols' grand strategy, their military organization and armaments, and their battle tactics. Turning from intelligence gathering to military operations, he offered practical advice on how to meet and defeat the coming Mongol onslaught, an attack that, providentially for the West, never came. What did occur was a modest but significant migration of Western missionaries and merchants to East Asia in the century following this pioneering journey.

• 한국항만경제학회지
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• 제22권1호
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• pp.39-59
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• 2006

The purpose of this paper is to analyze the competitiveness between Busan New Port and Shanghai's New Yangshan Port, on an island 20 miles off the Chinese mainland coast. For this aim, the paper examines backgrounds of Yangshan Port construction and its related projects, namely, Donghai Bridge and Luchao Logistics Park including operation strategies of Yangshan New Deepwater Port. The main results of this paper are as follows: Busan New Port has competitive advantage over Yangshan Port in terms of ideal location, especially in Asia-North America route, and connection between terminal and hinterland logistics park. Because Busan New Port is operated by fully on-dock system. Nevertheless, Yangshan Port has more strength in its centrality, port tariff and port productivity, which are represented by crane productivity, quay productivity and area productivity. Therefore, Korean ports are recommended by transformation from cargo attraction-type to cargo generation-type port through early activation of port logistics center along with Free Economic Zone.

• 한국통신학회논문지
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• 제31권12B호
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• pp.1049-1057
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• 2006

오버레이 멀티캐스트는 하드웨어적인 인프라의 구축 없이도 시스템의 자원과 네트워크 대역폭을 효율적으로 사용할 수 있는 기법이지만 IP 멀티캐스트와는 달리 중간 노드의 이탈이 발생하게 되어 멀티캐스트 트리의 복구가 필요하다. 본 논문에서는 이러한 결점을 보완하기 위해 각각의 노드가 가지는 Out Degree 자원을 사전에 예약하여 트리의 복구가 필요로 할 때 자원을 예약한 노드에게 바로 서비스를 요청하는 모델을 제안한다. 제안된 모델은 백업 노드의 도움으로 빠른 복구가 가능하고 복구된 노드들에게는 새로운 경로에서 발생한 지연시간의 영향을 최소화 했다. 시뮬레이션 결과를 통해 제안된 모델이 기존의 기법들 보다 적은 복구 시간이 소요되고 부모 노드의 이탈로 인해 많은 수의 노드가 영향을 받는 상황일수록 더욱 효과적인 방안임을 보여주고 있다.

• 산업경영시스템학회지
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• 제40권3호
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• pp.99-106
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• 2017

With the increased interest in the quality of life of modern people, the implementation of the five-day working week, the increase in traffic convenience, and the economic and social development, domestic and international travel is becoming commonplace. Furthermore, in the past, there were many cases of purchasing packaged goods of specialized travel agencies. However, as the development of the Internet improved the accessibility of information about the travel area, the tourist is changing the trend to plan the trip such as the choice of the destination. Web services have been introduced to recommend travel destinations and travel routes according to these needs of the customers. Therefore, after reviewing some of the most popular web services today, such as Stubby planner (http://www.stubbyplanner.com) and Earthtory (http://www.earthtory.com), they were supposed to be based on traditional Traveling Salesman Problems (TSPs), and the travel routes recommended by them included some practical limitations. That is, they were not considered important issues in the actual journey, such as the use of various transportation, travel expenses, the number of days, and lodging. Moreover, although to recommend travel destinations, there have been various studies such as using IoT (Internet of Things) technology and the analysis of cyberspatial Big Data on the web and SNS (Social Networking Service), there is little research to support travel routes considering the practical constraints. Therefore, this study proposes a new mathematical model for applying to travel route recommendation service, and it is verified by numerical experiments on travel to Jeju Island and trip to Europe including Germany, France and Czech Republic. It also expects to be able to provide more useful information to tourists in their travel plans through linkage with the services for recommending tourist attractions built in the Internet environment.

• International Journal of Computer Science & Network Security
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• 제21권12호
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• pp.1-8
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• 2021

In Mobile Ad-Hoc Network (MANET) Application, routing protocol is essential to ensure successful data transmission to all nodes. Ad-hoc On-demand Distance Vector (AODV) Protocol is a reactive routing protocol that is mostly used in MANET applications. However, the protocol causes Route Request (RREQ) message flooding issue due to the broadcasting method at the route request stage to find a path to a particular destination, where the RREQ will be rebroadcast if no Request Response (RREP) message is received. A scalable neighbor-based routing (SNBR) protocol was then proposed to overcome the issue. In the SNBR protocol, the RREQ message is only rebroadcast if the number of neighbor nodes less than a certain fix number, known as drop factor. However, since a network always have a dynamic characteristic with a dynamic number of neighbor nodes, the fix drop factor in SNBR protocol could not provide an optimal flooding problem solution in a low dense network environment, where the RREQ message is continuously rebroadcast RREQ message until reach the fix drop factor. To overcome this problem, a new broadcasting method as Dynamic SNBR (DSNBR) is proposed, where the drop factor is determined based on current number of neighbor nodes. This method rebroadcast the extra RREQ messages based on the determined dynamic drop factor. The performance of the proposed DSNBR is evaluated using NS2 and compared with the performance of the existing protocol; AODV and SNBR. Simulation results show that the new routing protocol reduces the routing request overhead, energy consumption, MAC Collision and enhances end-to-end delay, network coverage ratio as a result of reducing the extra route request messages.

• Korean Journal of Acupuncture
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• 제38권4호
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• pp.250-266
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• 2021

Objectives : This study was conducted to suggest new alternative methods to improve pharmacopuncture and Korean medicine research by analyzing the injection route, pharmacological effect, and status studies of Chinese herbal injections. Methods : 130 types of marketed and licensed Chinese herbal injection were searched from National Medical Products Administration (NMPA) of China. CNKI, PubMed, EMBASE, and the 2020 edition of the Chinese Pharmacopoeia were used to collect additional information. 'Herbal injection' and 'Chinese herbal injection' were used as keywords. All data were collected mainly on the treatment of Chinese herbal injection. But data which were not related to the relevant research or Chinese herbal injection were excluded. Results : Intramuscular injection accounted for more than half of the single injection route (51%). Acupoint and intramuscular injections accounted for 55% of dual injection routes. Acupoint, intravenous, and intramuscular injections accounted for the largest proportion (76%) of the multiple routes of injections. As for the pharmacological effect, injection for cardiovascular diseases accounted for 29%. About the number of raw herbal materials, single herbal material was the most common. Twelve intervention studies all tested intravenous injections, and half of them investigated cardiocerebrovascular diseases. All were given by intravenous injection. In the side effect section, the most common symptoms were nausea and vomiting. Conclusions : Through the results, it is expected to be used for research and development of new pharmacopuncture and herbal medicine.

• Bulletin of the Korean Chemical Society
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• 제26권12호
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• pp.2044-2046
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• 2005

• Bulletin of the Korean Chemical Society
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• 제30권11호
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• pp.2812-2814
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• 2009