• ETRI Journal
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• 제36권4호
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• pp.554-563
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• 2014

The burgeoning growth of real-time applications, such as interactive video and VoIP, places a heavy demand for a high data rate and guarantee of QoS from a network. This is being addressed by fourth generation networks such as Long-Term Evolution (LTE). But, the mobility of user equipment that needs to be handed over to a new evolved node base-station (eNB) while maintaining connectivity with high data rates poses a significant challenge that needs to be addressed. Handover (HO) normally takes place at cell borders, which normally suffers high interference. This inter-cell interference (ICI) can affect HO procedures, as well as reduce throughput. In this paper, soft frequency reuse (SFR) and multiple preparations (MP), so-called SFRAMP, are proposed to provide a seamless and fast handover with high throughput by keeping the ICI low. Simulation results using LTE-Sim show that the outage probability and delay are reduced by 24.4% and 11.9%, respectively, over the hard handover method - quite a significant result.

• International Journal of Naval Architecture and Ocean Engineering
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• 제10권1호
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• pp.37-47
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• 2018

Dynamic simulation is critical for electrical ship studies as it obtains the necessary information to capture and characterize system performance over the range of system operations and dynamic events such as disturbances or contingencies. However, modeling and simulation of the interactive electrical and mechanical dynamics involves setting up and solving system equations in time-domain that is typically time consuming and computationally expensive. Accurate assessment of system dynamic behaviors of interest without excessive computational overhead has become a serious concern and challenge for practical application of electrical ship design, analysis, optimization and control. This paper aims to develop a systematic approach to classify the sophisticated dynamic phenomenon encountered in electrical ship modeling and simulation practices based on the design intention and the time scale of interest. Then a novel, comprehensive, coherent, and end-to-end mathematical modeling and simulation approach has been developed for the latest Medium Voltage Direct Current (MVDC) Shipboard Power System (SPS) with the objective to effectively and efficiently capture the system behavior for ship-wide system-level studies. The accuracy and computation efficiency of the proposed approach has been evaluated and validated within the time frame of interest in the cast studies. The significance and the potential application of the proposed modeling and simulation approach are also discussed.

• 한국산학기술학회논문지
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• 제16권11호
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• pp.7508-7512
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• 2015

뇌파로 의도를 접속하여 기계를 작동하는 뇌-기기 접속(Brain-Computer Interface, BCI) 기반의 인간-로봇상호작용(Human-Robot Interaction, HRI) 플랫폼을 제안한다. 사람의 뇌파로 의도를 포착하고 포착된 뇌파 신호에서 의도를 추출하거나 연관시키고 추출된 의도로 기기를 작동하게 하는 포착, 처리, 실행을 수행하는 플랫폼의 설계, 운용 및 구현 과정을 소개한다. 제안된 플랫폼의 구현 사례로 처리기에 구현된 상호작용 게임과 처리기를 통한 외부 장치 제어가 기술되었다. BCI 기반 플랫폼의 의도와 감지 사이의 신뢰성을 확보하기 위한 다양한 시도들을 소개한다. 제안된 플랫폼과 구현 사례는 BCI 기반의 새로운 기기 제어 작동 방식의 실현으로 확장될 것으로 기대된다.

• 디자인학연구
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• 제17권1호
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• pp.299-308
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• 2004

컴퓨터 미디어 기술의 발전으로 정보를 표현하는 방법은 다양해졌다. 그러나 거대 데이터베이스를 정보 시각화함에 있어서 사용자의 요구에 부합하지 않는 복잡한 구조에 의해 데이터 의미 파악의 어려움이 생겼다. 사용자는 자신의 경험을 통한 지식 정보와 새로 제시되어지는 정보 시각화물을 결합하여 새로운 정보를 형성한다. 사용자가 신속하고 정확하게 데이터 상호간의 관계를 파악하고 새로운 정보를 탐색하기 위해서는 정보 시각화물의 데이터 표현이 구조화 되어야하고 그리고 의미 있는 심벌로 표현 되어져야한다. 삼차원 씬 그래픽 구조, 애니메이션의 동적 표현 요소, 그리고 데이터베이스의 데이터 구조를 상호대응 결합 및 조작 가능한 인터랙션을 제공하면 사용자가 스스로 데이터 탐색할 수 있는 정보 시각화 시스템을 제작할 수 있다. 사례로 가상공간 다이아그램, 폼(Form) 중심 다이아그램 그리고 시뮬레이션 다이아그램 등이 제시되었다.

• 한국멀티미디어학회논문지
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• 제5권1호
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• pp.94-104
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• 2002

본 연구는 하나의 도메인을 기반으로 하여 모델링된 Genus N 객체에 새로운 텍스쳐 매핑방법을 제안한 연구이다. 기존의 2D 텍스쳐 매핑의 문제점은 텍스쳐 도메인의 경계선이 객체상에 현저하게 나타난다는 사실이다. 이 현상은 부자연스러울 뿐 아니라 객체의 부드러운 연속성의 효과를 감소시킨다. 특히 무한대의 연속성을 가진 Genus N 객체는 경계선이 생성되지 않는 텍스쳐 매핑이 필수적이다. 이러한 텍스쳐 매핑을 위하여 multiperiodic 함수 즉, 불연속의 함수를 연속함수로 변형시키는 함수를 제안하였다. 하지만 사례에 따라 경계선이 보이는 텍스쳐가 더 사실적으로 보일 수 있다. 따라서 본 연구에서는 가중치를 이용하여 불연속과 연속 함수를 상호적으로 제어하도록 하였다.

• Nuclear Engineering and Technology
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• 제53권7호
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• pp.2195-2206
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• 2021

In order to mitigate the damage caused by accidents in nuclear power plants (NPPs), evacuation strategies are usually managed on the basis of off-site effects such as the diffusion of radioactive materials and evacuee traffic simulations. However, the interactive behavior between evacuees and the accident environment has a significant effect on the consequential gap. Agent-based modeling (ABM) is a method that can control and observe such interactions by establishing agents (i.e., the evacuees) and patches (i.e., the accident environments). In this paper, a radiological emergency evacuation model is constructed to realistically check the effectiveness of an evacuation strategy using NetLogo, an ABM toolbox. Geographic layers such as radiation sources, roads, buildings, and shelters were downloaded from an official geographic information system (GIS) of Korea, and were modified into respective patches. The dispersion model adopted from the puff equation was also modified to fit the patches on the geographic layer. The evacuees were defined as vehicle agents and a traffic model was implemented by combining the shortest path search (determined by an A ^* algorithm) and a traffic flow model incorporated in the Nagel-Schreckenberg cellular automata model. To evaluate the radiological harm to the evacuees due to the spread of radioactive materials, a simple exposure model was established to calculate the overlap fraction between the agents and the dispersion patches. This paper aims to demonstrate that the potential of ABM can handle disaster evacuation strategies more realistically than previous approaches.

• 한국산업융합학회 논문집
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• 제22권1호
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• pp.39-45
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• 2019

We propose an active color model based method for tracking motions of multiple human using a networked multiple-camera system in IoT space as a human-robot coexistent system. An IoT space is a space where many intelligent devices, such as computers and sensors(color CCD cameras for example), are distributed. Human beings can be a part of IoT space as well. One of the main goals of IoT space is to assist humans and to do different services for them. In order to be capable of doing that, IoT space must be able to do different human related tasks. One of them is to identify and track multiple objects seamlessly. In the environment where many camera modules are distributed on network, it is important to identify object in order to track it, because different cameras may be needed as object moves throughout the space and IoT space should determine the appropriate one. This paper describes appearance based unknown object tracking with the distributed vision system in IoT space. First, we discuss how object color information is obtained and how the color appearance based model is constructed from this data. Then, we discuss the global color model based on the local color information. The process of learning within global model and the experimental results are also presented.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2009년도 춘계학술대회
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• pp.781-784
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• 2009

현재 통신 방송 융합 서비스로 크게 대두되고 있는 서비스는 IPTV 서비스이다. IPTV 서비스는 대량의 방송 채널 선택, VoD서비스, 각종 양방향 응용 서비스 등과 같은 고품질의 다양한 방송 통신 융합 서비스 제공한다. IPTV에 대한 관련 기술이 빠르게 발전되면서 그에 대한 불법시청, 불법 복제, 접근권한 오남용 등 IPTV 콘텐츠 보안취약점에 대한 우려가 증가되고 있는 추세이다. 본 논문에서는 공개키 기반구조(PKI)의 공개키 인증서와 권한인증기반구조(PMI)의 속성인증서를 이용하여, 콘텐츠 서버 접근통제방안을 제안하였다.

• The Journal of Asian Finance, Economics and Business
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• 제8권4호
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• pp.517-527
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• 2021

While the two principles of lean manufacturing and time-driven activity-based costing (TDABC) have been established out of multiple incentives and do not follow the same particular targets, there is substantial commonality between them. In these conditions, the supply management of a multi-product system needs a rigorous production model to minimize costs. In this sense, this paper proposes an interactive model with the consideration of optimizing product-mix decisions using both lean development tools and TDABC. This paper proposes a qualitative approach using the case study of the Iraqi state company for battery production. The suggested model decreased manufacturing time and costs, along with some substantial reduction in idle production capacity by 26 percent in 2019, based on the findings of the case study. On the other hand, the proposed model gives two side advantages: an efficient division of costs on goods due to the use of time spent as a cost factor for products and cost savings due to the introduction of the lean manufacturing approach that reduces all additional costs and increases product-mix decisions. Furthermore, the analytical data gathered here suggests that the incorporation of lean management concepts and TDABC has a strong and important influence on product-mix decisions.

• International Journal of Computer Science & Network Security
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• 제21권5호
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• pp.222-230
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• 2021

The article reviews the issue of formation of information culture of social work bachelors in the process of their professional training. The main internal / external factors that determine the need for the information culture formation of social workers-to-be have been identified. To determine the levels of information culture formed in bachelors of social work criteria and their indicators have been substantiated. The model of information culture formation in BSW has been developed and implemented in Ukrainian universities under the following pedagogic conditions: organized informational environment; interconnection between general and professionally-directed courses; curriculum includes course directed on IC formation. The model contained interconnected components: aim - to achieve higher level of information culture formed; specific principles; content, interactive methods and forms of organization of educational process, methods of control and correction; components of information culture. The implemented mastered learning procedure has contributed to the leveling up of information culture formed in social work bachelors.