• 보건의료산업학회지
• /
• 제6권2호
• /
• pp.179-191
• /
• 2012

The study thus examined and analyzed 1,478 people aged 65 or older in the Korea National Health and Nutrition Examination Survey of 2010 to investigate the effects of differences in the elderly's general characteristics and depression & suicide ideation and in their subjective health perceptions and quality of life on their depression and suicide ideation. As a result, Significant differences in their suicide ideation were also caused by such quality of life variables as ill in bed, exercise capacity, self-management, daily activity, pain and uncomfortableness, and anxiety. The logistic analysis results of depression and suicide ideation according to the degree of subjective health perception show a significant finding that the better health perception they had compared with their very poor subjective health perception, the lower the odds ratio became. In the category of quality of life, only experience of uncomfortableness caused significant results on suicide ideation and depression. The results of the study will be of great use as basic data to intervene in the suicide route of the elderly and take measures to prevent suicide.

• 한국측량학회지
• /
• 제24권1호
• /
• pp.27-36
• /
• 2006

대부분의 국내 다목적 댐은 유역면적이 넓고 강우기 집중강우로 인하여 토양의 상당량이 유실되며, 유실된 토양입자는 하천이나 댐 저수지에 장기간 축적되어 저수용량의 감소와 수질관리에 어려움을 야기한다. 지금까지의 퇴적물 조사방법은 관측주기가 길고 측선법에 의한 퇴적정도를 관측하여 정확성 확보에 어려움이 많았다. 본 연구에서는 댐 저수지 퇴적물에 대한 정밀 관측을 위해 항공 LiDAR 기술을 활용하였으며, 퇴적물의 근원지를 추적하고 그 이동경로를 연구하였다. 토양유실에 영향을 주는 토양, 피복, 지형특성을 보다 세밀하게 분류함으로써 유실되는 퇴적물의 정확한 분포량과 유실 위치를 파악할 수 있었으며, 정확도가 향상된 고정밀 DEM을 이용하여 수로화된 흐름을 추적함으로써 퇴적물의 유실경로 분석에 신뢰성을 유지할 수 있었다.

• Journal of information and communication convergence engineering
• /
• 제8권1호
• /
• pp.1-5
• /
• 2010

In this paper, we propose for improving QoS in wireless micro cellular network using Cellular-IP/PRC(Paging Route Cache) with Paging Cache and Route Cache in Cellular-IP and propose for performance of realtime and non-real time handoff service using Handoff state machine Paging Route Cache. Although the Cellular-IP/PRC technology is devised for mobile internet communication, it bas its vulnerability in frequent handoff environment. On the other hand, Cellular IP combines the capability of cellular networks to provide high performance handoff and efficient location management of active and idle mobile users with the inherent flexibility, robustness and scalability found in IP networks. Also Cellular-IP/PRC use semi-soft handoff. During semi-soft hand off a mobile host may be in contact with either of the old and new base stations and receive packets from them. Packets intended to the mobile node are sent to both base stations and buffered, so when the mobile host eventually moves to the new location it can continue to receive packets without interruption. It should be suitable for realtime service such as multimedia traffic. But, much waste of resource will occur in this method, especially for non-real time services such as FTP and E-mail. Therefore, a new algorithm that performs different handoff according to characteristic of each traffic by use of reserved field in IP packet is proposed in this thesis. This hand off state machine using differentiated handoff improves quality of services in Cellular-IP/PRC. Suggested algorithm shows better performance than existing technology in wireless mobile internet communication environment. Matlab simulation results are improving QoS, show call drop and call blocking provided to Paging Router Cache during handoff state machine in Cellular-IP/PRC.

• 한국산학기술학회논문지
• /
• 제21권7호
• /
• pp.156-161
• /
• 2020

복수 무인기를 운영하는 환경에서 분산 임무 할당 알고리즘의 사용은 임무를 지휘 통제하는 중앙 관제 시스템이 없기 때문에 중앙 집중식 임무 할당 방식에 비해 무인기의 임무 중 탈락 이벤트로부터 보다 큰 강건성을 가지게 된다. 또한 무인기 스스로 상황을 인지하고 통신을 통해 임무를 재할당 하는 방식이기 때문에 임무 반경 또한 더욱 넓힐 수 있는 장점을 가지고 있다. 하드웨어 성능이 향상되고 비용이 감소함에 따라 임무 환경에서의 복수 무인기 운용에 대한 필요성이 증대되고 있으며, 작전 반경이 넓고 단일 고장에 강건한 분산 임무 할당 알고리즘에 대한 연구 필요성이 대두되고 있다. 본 논문은 대표적인 분산 임무할당 알고리즘인 CBBA를 기반으로 하여, 기존에 점 좌표로 단순화 되어 설정된 임무 종류를 점 좌표에 대한 감시 업무와 선형 경로의 정찰 임무로 구분하여 보다 현실에서의 임무 상황을 반영할 수 있도록 발전시켰다. 본 연구의 결과로서 복수무인기가 과다 임무가 부여된 상황에서 동일한 임무위치 및 보상을 갖는 상황을 몬테 카를로 시뮬레이션을 통해 최종 보상합(global reward)을 비교한다.

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

• Journal of Communications and Networks
• /
• 제13권5호
• /
• pp.499-510
• /
• 2011

Any server offering a routing service in the Internet would naturally be in competition for clients, and clients may need to utilize service from a specific server in order to achieve a desired result. We study the various properties of this competition, such as the fraction of route requests handled by a routing service provider and the fraction of total revenue obtained. As the routing service providers (i.e., servers or routers in this context) compete, they may alter behavior in order to optimize one of the above properties. For example, a service provider may lower the price charged for its service, in order to increase the number of clients served. Our models are based on servers offering a routing service to clients within representative network topologies based on actual Internet sub-graphs. These models provide, a framework for evaluating competition in the Internet. We monitor key aspects of the service, as several variables are introduced into the models. The first variable is the fraction of client requests that will pay more for a better quality route. The remaining requests are normal client requests that are satisfied by the most economical route. The second variable is the fraction of servers who choose to lower service prices in order to maximize the number of client requests served. As this fraction increases, it is more likely that a server will lower the price. Finally, there are some resource constraints applied to the model, to increase the difficulty in providing a routing solution, i.e., to simulate a realistic scenario. We seek to understand the effect on the overall network, as service providers compete. In simple cases, we show that this competition could have a negative impact on the overall efficiency of a service. We show that the routing variety present in the larger models is unable to mask this tendency and the routing service performance is decreased due to competition.

• 한국인터넷방송통신학회논문지
• /
• 제23권2호
• /
• pp.1-6
• /
• 2023

본 연구는 일정 관리 애플리케이션을 효율적으로 사용할 수 있도록 연구, 개발하는 데 목적이 있다. 사람들은 자신이 해야 할 일들을 기억하기 위해 일정 관리 애플리케이션을 사용하고, 목적지에 제때 도착하기 위해 지도 애플리케이션을 사용한다. 본 연구에서는 사용자들이 애플리케이션을 편리하게 사용할 수 있도록 A^* 알고리즘을 사용하여 일정에 대한 최적의 동선을 추천해 주고 이를 지도 API를 활용하여 시각적으로 제공하는 애플리케이션을 개발하였다. 현재 사용되고 있는 캘린더, 지도, 스케줄 애플리케이션들을 비교 분석하여 단점을 보완하고 장점을 융합한 애플리케이션 개발을 위해 여러 가지 Open Maps API들을 비교하였다. 그리고 사용자가 등록한 일정에 대하여 시간, 장소에 따라 동선을 추천하기 위한 최적의 알고리즘을 적용한 애플리케이션 개발 결과를 기술하였다.

• 한국분무공학회지
• /
• 제22권4호
• /
• pp.218-224
• /
• 2017

In order to improve the quality of air in urban areas, the emission regulations are being strengthened by the government. The on-road test of light-duty vehicles was started with PEMS because certification test mode does not sufficiently reflect on-road conditions. Therefore, The PEMS-based test was implemented from Sep. 2017 in Europe and Korea. However, this is lack of data on various on-road patterns in Korea. The purpose of the present study has analyzed the effect of speed per acceleration and acceleration on NOx emission on-road driving. The test route consisted of urban, rural, and motorway in Seoul. This study has been conducted by Euro-6 vehicles using on SCR system with PEMS. The on-road emission characteristics were evaluated by moving averaging windows (MAW) method. In results, RDE-NOx by severe driving pattern has been 1.4 times higher than soft driving pattern NIER Route 1.

• 한국항해항만학회지
• /
• 제29권5호
• /
• pp.371-376
• /
• 2005

최근 낙도 보조항로의 운영에 있어서 선박 취항명령후 운영사업자의 계속적인 사업수행으로 일반항로에 비해 경영개선노력이 부진하거나 서비스의 질이 저하되는 등 여러 가지 문제점이 나타나고 있다. 따라서 본 연구에서는 낙도 보조항로 운영주체를 검토하여 개선방향을 제시하고자 AHP 기법을 이용한 실증연구를 수행하였다. 연구결과 보조항의 사업자에 대한 경영평가제를 도입하여 사업자 스스로 지속적인 경영개선 노력을 유도함이 바람직할 것으로 보인다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제13권7호
• /
• pp.3386-3411
• /
• 2019

Secured and reliable routing is a crucial factor for improving the performance of Wireless Mesh Networks (WMN) since these networks are susceptible to many types of attacks. The existing assumption about the internal nodes in wireless mesh networks is that they cooperate well during the forwarding of packets all the time. However, it is not always true due to the presence of malicious and mistrustful nodes. Hence, it is essential to establish a secure, reliable and stable route between a source node and a destination node in WMN. In this paper, a trust based secure routing algorithm is proposed for enhancing security and reliability of WMN, which contains cross layer and subject logic based reliable reputation scheme with security tag model for providing effective secured routing. This model uses only the trusted nodes with the forwarding reliability of data transmission and it isolates the malicious nodes from the providing path. Moreover, every node in this model is assigned with a security tag that is used for efficient authentication. Thus, by combining authentication, trust and subject logic, the proposed approach is capable of choosing the trusted nodes effectively to participate in forwarding the packets of trustful peer nodes successfully. The simulation results obtained from this work show that the proposed routing protocol provides optimal network performance in terms of security and packet delivery ratio.