• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.676-678
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• 2004

이동 임시 무선망은 잦은 망 구성의 변화, 라우터의 수, 제한된 사용 자원 등 기존 유선 네트워크와는 다른 특성들을 가지게 된다. 따라서 기존의 유선 네트워크에서 사용하던 라우팅 프로토콜들을 이동 임시 무선망에 그대로 적용시킨다면 많은 문제점들이 발생하게 된다. 본 논문에서 제안하는 라우팅 프로토콜은 이동 임시 무선망의 특성을 고려하여, 네트워크 내의 이동 호스트를 멀티 홉을 갖는 클러스터로 묶고. 클러스터 헤드로 하여금 자신의 멤버 호스트들과 이웃 클러스터들의 헤드 정보를 유지하게 하여, 경로 설정에 대한 요구가 있을 때에 적은 지연 시간과 적은 패킷으로 목적지까지의 최단 경로를 설정할 수 있도록 한다. 또한 경로 설정과 데이터 전송 모두가 클러스터 헤드를 이용한다. 이러한 경우 모든 데이터와 경로설정 시 발생하는 패킷들이 클러스터 헤드로 집중되어 네트워크 부하가 발생하게 되는데 본 제안에서는 네트워크의 부하를 줄이기 위하여 후보 클러스터 헤드를 이용하는 방법을 제시한다.

• The Journal of the Acoustical Society of Korea
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• v.39 no.1
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• pp.16-23
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• 2020

In High-Intensity Focused Ultrasound (HIFU) treatment, effective localization of HIFU focus is important for developing a safe treatment plan. While Magnetic Resonance Imaging guided HIFU (MRIgHIFU) can visualize the ultrasound path during the treatment for localizing HIFU focus, it is challenging in ultrasound imaging guided HIFU (USIgHIFU). In the present study, a real-time ultrasound beam visualization technique capable of localizing HIFU focus is presented for USIgHIFU. In the proposed method, a short pulse, with the same center frequency of an imaging ultrasound transducer below the regulated acoustic intensity (i.e., Ispta < 720 mW/㎠), was transmitted through a HIFU transducer whereupon backscattered signals were received by the imaging transducer. To visualize the HIFU beam path, the backscattered signals underwent dynamic receive focusing and subsequent echo processing. From in vitro experiments with bovine serum albumin gel phantoms, the HIFU beam path was clearly depicted with low acoustic intensity (i.e., Ispta of 94.8 mW/㎠) and the HIFU focus was successfully localized before any damages were produced. This result indicates that the proposed ultrasound beam path visualization method can be used for localizing the HIFU focus in real time while minimizing unwanted tissue damage in USIgHIFU treatment.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.1
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• pp.34-42
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• 2012

Life and Property damage has increased during traffic congestion and isolation because natural disasters such as flood and landslide have occurred every year. When disaster occurs, if there is insufficient information in advance when entering the flooding areas which subsequently cause confusion. In this paper, we developed the system that could provide display of detour route using disaster information and evacuation route in disaster areas. User will receive result of analysis using smart phone application to prevent additional damages when disaster areas were entered by manager.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.15 no.2
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• pp.183-192
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• 2020

This study conducted an exploratory study to derive the success factors of entrepreneurial marketing for startups. Through Delphi analysis, we derived the items of proactive orientation, risk management, innovation, opportunity driven, resource leveraging, customer intensity, value creation, price setting, marketing communication, channel management, product development, sales and marketing information management. The importance and execution of success factors were measured through IPA analysis. The first quadrant(keep up the good work) has proactive orientation, risk management, resource leveraging, customer intensity. The second quadrant(concentrate here) has innovation. The third quadrant(low priority) has channel management, sales, marketing information management. The fourth quadrant(possible overkill) has prices setting, product development. These results showed that the success factors of startup's entrepreneurial marketing were proactive orientation, risk management, innovation, opportunity driven, resource leveraging, customer intensity and value creation.

• Journal of KIISE:Information Networking
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• v.29 no.1
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• pp.57-64
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• 2002

Since most of the current route selection algorithms use the shortest path algorithm, network resources can not be efficiently used also traffics be concentrated on specific paths resulting in congestgion. In this paper we propose the statistical route selections(SRS) algorithm which adopts a statistical mechanism to utilize the network resource efficiently and to avoid congestion. The SRS algorithm handles requests on demand and chooses a path that meets the requested bandwidth. With the advent of the MPLS it becomes possible to establish an explicit LSP which can be used for traffic load balancing. The SRS algorithm finds a set of link utilizations for route selection, computes link weights using statistical mechanism and finds the shortest path from the weights. Our statistical mechanism computes the mean and the variance of link utilizations and selects a route such that it can reduce the variance and the number of congested links and increase the utilization of network resources. Throughout the simulation, we show that the SRS algorithm performs better than other route selection algorithms on several metrics like the number of connection setup failures and the number of congested links.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.10
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• pp.1248-1253
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• 2019

Using current evacuation methods, a crew describes the physical location of an accident and guides evacuation using alarms and emergency guide lights. However, in case of an accident on a large and complex building, an intelligent and effective emergency evacuation system is required to ensure the safety of evacuees. Therefore, several studies have been performed on intelligent path finding and emergency evacuation algorithms which are centralized guidance methods using gathered data from distributed sensor nodes. However, another important aspect is effective rescue guidance in an emergency situation. So far, there has been no consideration on the efficient rescue guidance scheme. Therefore, this paper proposes the genetic algorithm based emergency rescue guidance method using distributed wireless sensor networks. Performance evaluation using a computer simulation shows that the proposed scheme guarantees efficient path finding. The fitness converges to the minimum value in reasonable time. The density of each exit node is remarkably decreased as well.

• Journal of the Korea Society for Simulation
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• v.19 no.2
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• pp.91-98
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• 2010

Conventional path-finding has focused on finding short collision-free paths. However, as computer games become more sophisticated, it is required to take tactical information like ambush points or lines of enemy sight into account. One way to make this information have an effect on path-finding is to represent a heuristic function of a search algorithm as a weighted sum of tactics. In this paper we consider the problem of learning heuristic to optimize path-finding based on given tactical information. What is meant by learning is to produce a good weight vector for a heuristic function. Training examples for learning are given by a game level-designer and will be compared with search results in every search level to update weights. This paper proposes a learning algorithm integrated with search for tactical path-finding. The perceptron-like method for updating weights is described and a simulation tool for implementing these is presented. A level-designer can mark desired paths according to characters' properties in the heuristic learning tool and then it uses them as training examples to learn weights and shows traces of paths changing along with weight learning.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.3
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• pp.453-458
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• 2013

Aside from the issues like energy saving and maximizing network lifetime. WMSN has another issue to deal with: support of quality of service(QoS) which is required especially for handling real-time data such as object tracking and data gathering. This paper proposes a multipath routing algorithm considering the distance to sink node, energy level and link quality of neighbour nodes. Proposed algorithm supports multipath routing path with high quality links. Hence it helps to reduce a power consumption concentration that happens in particular set of nodes along the frequently selected route. It also specifies a service quality pattern and a service quality level depending on traffic pattern. By doing this, the proposed algorithm can realize a differentiated service with QoS guaranteed data transmission.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10e
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• pp.346-348
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• 2002

차량 항법 시스템(Car Navigation System)은 요즘 많은 발전을 거듭하여 차량 이용시 사용자가 가고자하는 목적지까지의 길을 쉽게 안내하고 있다. 이런 기술의 발전은 단순한 정적인 길 안내(Static Route Guidance) 뿐만 아니라. 동적인 길 안내(Dynamic Route Guidance)를 함으로써 자동차 운전자가 쉽고 빠른 길을 안내 받을 수 있게 되었다. 그러나 이러한 교통정보는 매우 변화가 심하므로 최초로 경로를 전송 받은 후 그 경로상에 교통정보가 변화하였다면, 이미 전송 받은 경로는 실시간으로 적극적으로 대응할 수 없고 실제 막히는 길로 안내할 수 있다. 목적지까지의 거리가 먼 경우 이런 현상이 더욱 심하게 나타날 수 있다. 이런 경우 운전자는 실제로는 막히는 길로 안내 받을 수 밖에 없다. 이런 문제점을 해결하기 위해 교통정보를 수집하는 기존의 시스템에 Ad Hoc 네트워킹이 가능한 시스템을 탑재한 교통정보 수집 차량(Probe Car)을 이용한다. 정보 수집 차량이 극심한 정체를 발견하면 근처를 지나는 경로를 가진 차량에게 이를 전달하여 새로운 경로를 다운받을 수 있도록 한다. 이런 방법은 Ad Hoc Relaying System〔l〕을 이용하여 가능하며, 센터에 수집되고 가공되는 시간을 최대한 줄일 수 있으며, 센터의 통신 오버헤드를 최소화할 수 있다. 또한 기지국에 호가 집중되어 call blocking이 발생함 경우에 이를 해결할 수 있다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.338-340
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• 2021

Among the recent natural disasters, flood damage is concentrated in the summer, leading to casualties or property damage due to the typhoon's rainy season. Much research is being done to reduce this damage. In this paper, we design and implement a system that detects paths and provides them to users using shortest-distance algorithms in the event of such sudden flooding. The proposed system uses QGIS to detect paths using topographical data that generated tracks and pointers. In addition, other shortest paths are detected and provided to users when sudden flooding occurs during evacuation to routes detected through scenarios. Therefore, it is assumed that the proposed system will allow users to safely evacuate from the risk of future disaster safety accidents.