• Journal of KIISE:Information Networking
• /
• v.30 no.5
• /
• pp.573-580
• /
• 2003

Increasing user demand for the more bandwidths in wireless communications has motivated a new challenge to utilize the benefits of wireless ATM technology This paper focuses on how to provide IP services to a mobile user over wireless ATM networks. By enhancing the NHRP standard, several shortcomings are improved that are resulted from the naive combinations of Mobile IP over ATM and IP over wireless ATM. This paper presents a mobile location management algorithm that is referred to as the Mobile NHRP scheme. The mobile tracking procedure and the mobile locating procedure are explicitly defined in the proposed scheme. On the locating procedure, the source station may obtain the current location of the destination from NHSs(Next Hop Servers). Therefore the optimized connection can be setup directly. The total costs per move and per setup over ATM/IP overlaid networks are estimated.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.9
• /
• pp.1666-1674
• /
• 2008

In this paper, various forms of technical methods as well as comparison analysis on constructing optical subscriber network were studied to find the most economical installation method in the future. Comparison analysis has been focused on the three popular types of optical subscriber networks in Korea, such as VDSL2, Ethernet-LAN and FTTH-R. A study is conducted on the initial installation investment per subscriber, equipment failure rate as well as power consumption per subscriber. As a results, FTTH-R network will be the most economical method in the future, but a gradual switch which undergoes a UTP-fiber hybrid method as the midway process is preferable in considering the existing installed copper UTP subscriber cables.

• Journal of Convergence for Information Technology
• /
• v.8 no.6
• /
• pp.193-199
• /
• 2018

The commonly used delivery system for online merchandise has potential problems, not only missing but also criminal case. Also, the contemporary Kiosk type approach for delivery system has some problems in an initial installation cost, expense of management system and especially security weaknesses in the wireless communication. To resolve these issues, this paper is proposing a securely unmaned smart locker system that can handle up to 64 parcels. This is easily controlled and monitored by a smartphone. In addition to the system, an algorithm is proposed to make the security of wireless communications better. Finally, a method is proposed to minimize the cost of delivery by using centralized server.

• Journal of Advanced Navigation Technology
• /
• v.21 no.6
• /
• pp.572-578
• /
• 2017

As the demand of high accuracy positioning for dynamic users increases, Network RTK is actively researched for dynamic users. Network RTK is a system which provides precise positioning in the range of about 50 to 70km radius using carrier phase measurements from several reference stations. By configuring multiple clusters, which provide Network RTK corrections independently, as a single system, it could provide precise positioning for a wider area. In this paper, we have studied how to efficiently operate multiple clusters in the Korean Peninsula. We analyzed the computational load according to the configuration of a multi-cluster system and proposed a method of selecting the main reference station and system infrastructure configuration for efficient operation. In order to analyze the effects of each proposed method, 71 clusters were constructed using the reference stations of the National Geographic Information Institute and simulations were conducted. As a result of the simulation, system computation amount was reduced by 66 % and system configuration cost was reduced by 90 %.

• 한국정보통신설비학회:학술대회논문집
• /
• 2009.08a
• /
• pp.40-44
• /
• 2009

지하구는 도시의 신경망이라 할 수 있는 통신, 전력, 상수도, 난방, 쓰레기 처리시설 등 도시 운용/관리를 위한 주요시설물을 안전하게 수용하고, 유지 관리하기 위한 시설로 IT기술을 이용하여 수용된 시설을 효과적으로 유지/관리하고, 재난으로부터 안전하게 보호함과 동시에 최소의 비용과 에너지로 수용된 시설물을 유지관리하기 위한 연구가 많이 진행되고 있다. 따라서 본 논문에서는 지하구(공동구, 통신구, 전력구)의 운용 및 유지관리와 지하구에서 발생될 수 있는 각종 재난에 대응하기 위한 지하구 운용 및 유지관리에 대해 알아보고, 지하구 내부에 수용된 시설물을 효과적으로 유지관리하고 재난에 신속히 대응하기 위한 지하구 환경모니터링 시스템에 대해 기술 하고자 한다. 지하구 환경모니터링 시스템은 지하구 내부에는 전력, 상수도, 통신, 난방 등 다양한 시설물이 수용되어 있으며, 이러한 시설물의 부식, 고장 등으로부터 보호하기 위해 지하구내부의 환기시스템의 송풍기와 지하수와 기상재해로 인한 지하구 및 수용시설물의 침수를 막기 위한 양수펌프에 대해 실시간 상태모니터링 통해 송풍기 및 펌프의 고장여부를 판단하여 관리자에게 알림으로써 관리자가 신속하게 대응 할 수 있도록 하였다. 송풍기의 제어는 지하의 내부와 외부에 설치된 온/습도 센서를 통해 지하구 내부환경을 최적으로 유지할 수 있도록 함으로써 쾌적한 지하 내부환경 유지하고, 급/배기가 필요할 경우에만 송풍기를 가동함으로써 에너지를 절약 할 수 있으며, 화재, 침수 등에 대한 재난시 환풍기의 급/배기, 정지 등을 신속하게 제어할 수 있도록 하였다. 또한 지하구내부에서 발생된 재난을 유/무선을 이용하여 신속하게 지하구 주변의 장치(U-Pole 또는 통합컨트롤러)를 통해 경보를 전파함으로써 주변 시민들이 안전하게 대피할 수 있도록 하였다. 그리고 지하구 환경모니터링 시스템을 검증하기 위해 실제 지하구 및 실험실에 시스템 및 Test Board을 설치하여 운용시험을 실시 하였다.

• Journal of Advanced Navigation Technology
• /
• v.21 no.5
• /
• pp.443-449
• /
• 2017

Swarm of low-cost UAVs for search mission has benefit in the sense of rapid search compared to use of single high-end UAV. As the number of UAVs forming swarm increases, not only the time for the mission planning increases, but also the system to operate UAVs has excessive burden. This paper addresses a decentralized area search algorithm adequate for multiple UAVs which takes advantages of flexibility, robustness, and simplicity. To down the cost, it is assumed that each UAV has limited ability: close-communication, basic calculation, and limited memory. In close-communication, heath conditions and search information are shared. And collision avoidance and consensus of next search direction are then done. To increase weight on un-searched area and to provide overlapped search, the score function is introduced. Performance and operational characteristics of the proposed search algorithm and mission planning logic are verified via numerical simulations.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.12
• /
• pp.2777-2784
• /
• 2012

To support complex business environment. the enterprise information system requires prompt and flexible response to altered conditions. The development of collaboration among information systems in accordance with changes in enterprises' business environment brings about the problems of duplication of the existing business services and increase in costs of maintenance. In order to supplement and resolve such problems, researches on ontology are under way. Ontology can support the semantic interoperability of Web service by describing the resources of particular business domains and the relationships among them. This thesis suggests ontology that supports interoperability among services. The constructed ontology is designed into the service area, the meta area, and the instance area, which can support the collaboration efficiently by providing the link between the interactivity among businesses and the data. The register and call of constructed ontology are carried out with the interaction of the three areas, that is, the service area, the instance area and the meta area that supports the common elements. The efficiency of the proposed ontology is evaluated by comparing with an existing Web service ontology.

• Proceedings of the KIEE Conference
• /
• 2003.07d
• /
• pp.2331-2333
• /
• 2003

전력계통의 원방감시제어시스템(SCADA)은 원방의 전력계동을 화면에 표시하고 감시하며 필요한 제어명령을 실행하는 시스템을 말한다. 철도청의 기존 전력계통 제어시스템은 UNIX를 기반으로 하여 특별히 교육 받은 운용자만이 감시제어 및 관리할 수 있고 구축비용이 많이 소요되며 지역 사무소에서 운용되기 때문에 원격지의 전력계통 사고의 경우 시스템 운용자는 현장의 근무자와 연락하여 사고의 원인을 파악하고 조치해야 하는 단점이 있다. 또한 새로운 통합 SCADA 시스템이 구축되면서 기존 지역사무소에서 운용하던 전력계통 제어시스템이 없어지고 중요 역사마다 지역사무소의 전력계통 제어시스템을 대체할 수 있는 소규모 전력계통 제어시스템의 설치가 요구되고 있다. 본 논문에서는 기존 UNIX를 기반으로 한 SCADA 시스템의 기능을 모두 수용하고 현장의 근무자들이 쉽게 감시제어 및 유지보수까지도 할 수 있는 경제적인 전력 계통 제어시스템을 개발하고자 한다. 소규모 전력 계통 제어시스템을 개발하기 위해 Cimon 이라는 산업자동화프로그램을 이용하였으며 철도청 철암 역사에 직접 시스템을 설치하여 원격소 장치(RTU)와 새로 추가 설치된 전자식배전반을 동시에 수용할 수 있는 소규모 전력계통 제어시스템을 개발하고 실험하였다.

• Journal of the Korea Society for Simulation
• /
• v.18 no.3
• /
• pp.139-146
• /
• 2009

Recently, software industry regarding national defense increases system development of distributed simulation system of M&S based to overcome limit of resource and expense. It is one of key technologies for offering of mutual validation among objects and reuse of objects which are discussed for developing these systems. RTI, implementation of HLA interface specification as software providing these technologies uses Federation Object Model for exchanging information with joined federates in the federation and each federate has a characteristic that is supposed to have identical FOM in the federation. This paper presents a characteristic of Base Object Model, SISO standardization for improving reuse and interoperability of Federation Object Model applied simulation network manager based HLA/RTI and suggests method of designing the structure of simulation network manager through the modularity of Federation Object Model.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.50 no.1
• /
• pp.13-20
• /
• 2022

Aircraft weight is an important factor affecting performance and fuel efficiency. In the conceptual design stage of the aircraft, the process of balancing cost and weight is performed using empirical formulas such as fuel consumption cost per weight in estimating element weight. In addition, when an airline operates an aircraft, it promotes fuel efficiency improvement, fuel saving and carbon reduction through weight management activities. The relationship between changes in aircraft weight and changes in fuel consumption is called the cost of weight, and the cost of weight is used to evaluate the effect of adding or reducing weight to an aircraft on fuel consumption. In this study, the problems of the existing cost of weight calculation method are identified, and a new cost of weight calculation method is introduced to solve the problem. Using Breguet's Range Formula and actual flight data of the A350-900 aircraft, two weight costs are calculated based on take-off weight and landing weight. In conclusion, it was suggested that it is reasonable to use the cost of weight based on the take-off weight and the landing weight for other purposes. In particular, the cost of weight based on the landing weight can be used as an empirical formula for estimating element weight and optimizing cost and weight in the conceptual design stage of similar aircraft.