• Journal of Industrial Technology
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• v.27 no.B
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• pp.37-42
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• 2007

A mobile ad hoc network (MANET) is a kind of wireless ad hoc network. It is a self-configuring network of mobile nodes connected by wireless links. Infostation is a lower cost and low power system that provides very high bit rate with limited coverage. In this study, we propose search and rescue system that combines MANET of climbers with Infostations. A climber shares location information of climbers with other climbers while climbing, and delivers the information to Infostations. This system is an intermittent network due to the mobility of nodes. From the system, we can track the locations of missing climbers. Ultimately, proposed system achieves low cost and reduces memory requirement using Infestations. We also analyze the performance of the proposed system by simulation. From the performance analysis results, we expect that the proposed system will be very useful to early detect climbers' locations in emergency situations in Korea mountain areas.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.625-628
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• 2013

기술이 발달함에 따라 USB메모리, 보안 SD카드, 보안인증토큰 등 이동형 저장 매체도 비약적인 발전을 하고 있다. USB의 가격이 저렴해지고 작아지면서 용량의 확장도 증가하여 다양한 이용을 할 수 있게 되었다. 하지만 분실율이 높고 보안성이 낮아 다수의 사용자에게 중요한 회사의 기밀이나 개인의 인적 사항들이 노출 될 수 있다. 이를 위해 PUF를 이용하여 플래시 메모리 마다 고유키를 저장, 생성하여 외부 유출이 없이 사용자 인증을 하기 위한 플래시 드라이버의 구조 및 프로토콜을 제안하고자 한다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.292-294
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• 2003

최근들어 IT 산업이 급속도로 발전하면서, 리소스가 제한된 작은 기기들의 사용이 비약적으로 증가하는 추세에 있다. 이들 기기들에 플랫폼 독립성(Platform Independency), 보안성(Security), 이동성(Mobility) 등의 장점을 포함하고 있는 자바 환경을 적용하기 위해 연구가 계속되고 있다. 임베디드 시스템이나 모바일 시스템과 같이 자원이 제한적인 다양한 기기들에는 자바 가상 머신을 경량화한 최소 크기의 자바 플랫폼에 대한 Configuration인 CLDC(Connected, Limited Device Configuration)에서 정의하고 있는 K 가상 머신(K Virtual Machine: KVM)을 탑재한다. 본 논문에서는 실시간 운영체제로 iRTOS$^{TM}$을 사용하는 기기에서 KVM을 탑재할 때 필요한 메모리 체계를 설계하고 구현한 내용을 설명한다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.805-807
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• 2004

최근 IT 산업의 발전과 더불어, 리소스가 제한된 소형 기기들의 사용이 비약적으로 증가하고 있는 추세이다. 자바는 플랫폼 독립성(Platform Independency), 보안성(Security), 네트워크 이동성(Network Mobility) 등의 장점을 가지고 있어, 이러한 소형 기기들에 자바 환경을 적용하게 되면 여러 가지 이점을 가지게 된다. 임베디드 장치나 모바일 같은 제한된 리소스를 사용하는 기기들에는 SUN 사의 CLDC(Connected, Limited Device Configuration)에서 정의하고 있는 K 가상 머신(K Virtual Machine: KVM)을 탑재하여 사용하게 된다. 본 논문에서는 실시간 운영체제 iRTOS$^{TM}$와 KVM 을 탑재한 소형 기기에서 좀더 효율적으로 KVM 의 메모리를 관리하기 위한 Garbage Collection기법을 설계하고 구현한 내용을 설명한다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.682-684
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• 2004

IT 산업이 발전하고, 제한된 리소스를 탑재한 소형 기기들의 사용이 증가함에 따라, 이러한 소형 기기들의 성능을 극대화하고 안정된 서비스를 제공하기 위한 다양한 핵심 소프트웨어 플랫폼들이 제안되고 있다. 자바는 플랫폼 독립성(Platform Independency), 보안성(Security), 네트워크 이동성(Network Mobility) 둥의 장점을 가지고 있어, 많은 분야의 소형 기기들에서 핵심 소프트웨어 플랫폼으로 채택되고 있다. 임베디드 장치나 모바일 같은 제한된 리소스를 사용하는 기기들은 자바의 소프트웨어 플랫폼중의 하나인 K 가상 머신(K Virtual Machine: KVM)을 탑재하여 사용하고 있다. 본 논문에서는 제한된 리소스를 사용하는 소형 기기의 KVM 에서 좀 더 효율적으로 힙 메모리 관리를 하기 위한 MCCL(Mark-Compact-Compress-Lazy Allocate) 가비지 콜렉션 기법을 설계하고 구현한 내용을 설명한다.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.343-343
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• 2011

저온에서의 Thin Film Transistor (TFT) 혹은 Nonvolatile memory (NVM) 등의 MOS 구조 소자들의 높은 전기적 특성에 관한 연구들이 진행 되면서 mobility와 stability 그리고 구조화의 용이성에 대한 연구가 진행됨에 따라 amorphous silicon의 결정화를 통해 전기적 특성을 향상 시킨 Nanocrystalline silicon (nc-Si)/Microcrystalline silicon (${\mu}c$-Si)에 대한 연구가 관심을 받고 있다. 본 논문에서는 ${\leq}300^{\circ}C$에서 Inductively coupled plasma chemical vapor deposition를 이용한 TFT을 제작하였다. 가스비, 온도, 두께에 따른 결정화 정도를 Raman spectra를 통해 확인한 후 Bottom gate와 Top gate 구조의 TFT를 제작 하고 결정화에 따른 전기적 특성 향상과 그의 덧붙여 플라즈마 처리를 통한 특성 향상을 확인 하였다.

• The Journal of Korean Physical Therapy
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• v.27 no.4
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• pp.252-257
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• 2015

Purpose: The purpose of this study was to assess psychometric properties of the Korean version of the Stroke Impact Scale 3.0 (K-SIS 3.0) in patients with stroke. Methods: Patients with stroke longer than 3 months were invited to participate in the study at specialized rehabilitation centers in Busan. Information on patients was collected using Mini-Mental State Examination (MMSE), Modified Bathel Index (MBI), Beck Depression Index (BDI), WHODAS 2.0-12 item, and K-SIS. Floor and ceiling effects of each domain of K-SIS were examined. The internal consistency of each domain of the K-SIS was calculated using Cronbach's ${\alpha}$. Correlation between K-SIS and each scale was assessed using Spearman's correlation coefficient. Results: Ninety subjects participated in the study. The K-SIS was found to have excellent internal consistency (Cronbach's ${\alpha}=0.93$). Each domain of the consistency ranged from 0.86 to 0.94, except the emotion (${\alpha}=0.51$). Significant correlations were observed between MMSE and domains of memory and thinking, and communication (r=0.48 and 0.52 respectively). BDI was negatively related to domains of emotion, ADL, mobility, and participation (r=-0.43, -0.49, -0.52 and -0.33 respectively). Specific daily activity (MBI) and general functioning (WHODAS 2.0) were also found to be closely related to the domains of ADL, mobility, and participation (ranging from r=-0.41 to r=-0.59). No ceiling and floor effect was observed. Conclusion: Excellent reliability and validity of K-SIS were obtained in the study and it could be suggested that K-SIS may be used for patients with stroke for collection of information on functioning in the clinical context.

• Journal of the Korea Society of Computer and Information
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• v.17 no.5
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• pp.81-91
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• 2012

Recently, as location-determination of indoor users is available with the development of variety of localization techniques for indoor location-based service, diverse indoor location based services are proposed. Accordingly, it is necessary to develop individualized POI recommendation service for recommending most interested points of large-scale commercial spaces such as shopping malls and departments. For POI recommendation, it is necessary to study the method for exploring location which users are interested in location with considering user's mobility in large-scale commercial spaces. In this paper, we proposed POI recommendation system with the definition of users' as 'Stay point' in order to consider users' various interest locations. By using the proposed algorithm, we analysis users' Stay points, then mining the users' visiting pattern to finished the proposed. POI Recommendation System. The proposed system decreased data more dramatically than that of using user's entire mobility data and usage of memory.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.11
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• pp.27-32
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• 1999

Metal-ferroelectric-semiconductor devices by susing rapid thermal annealed $LiNbO_3/Si$(100) structures were fabricated and demonstrated nonvolatile memory operations. The estimated field-effect electron mobility and transconductance on a linear region of the fabricated FET were about $600cm^2/V{\cdot}s$ and 0.16mS/mm, respectively. The ID-VG characteristics of MFSFET's showed a hysteresis loop due to the ferroelectric nature of the $LiNbO_3 films. The drain current of the on state was more than 4 orders of magnitude larger than the off state current at the same read gate voltage of 0.5V, which means the memory operation of the MFSFET. A write voltage as low as ${\pm}3V$, which is applicable to low power integrated circuits, was used for polarization reversal. The ferroelectric capacitors showed no polarization degradation up to $10^{10}$ switching cycles with the application of symmetric bipolar voltage pulse (peak-to-peak 6V, 50% duty cycle) of 500kHz.

• The KIPS Transactions:PartD
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• v.16D no.2
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• pp.237-248
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• 2009

Recently, based on dynamic location or mobility of moving object, many researches on pattern mining methods actively progress to extract more available patterns from various moving patterns for development of location based services. The performance of moving pattern mining depend on how analyze and process the huge set of spatio-temporal data. Some of traditional spatio-temporal pattern mining methods[1-6,8-11]have proposed to solve these problem, but they did not solve properly to reduce mining execution time and minimize required memory space. Therefore, in this paper, we propose new spatio-temporal pattern mining method which extract the sequential and periodic frequent moving patterns efficiently from the huge set of spatio-temporal moving data. The proposed method reduces mining execution time of $83%{\sim}93%$ rate on frequent moving patterns mining using the moving sequence tree which generated from historical data of moving objects based on hash tree. And also, for minimizing the required memory space, it generalize the detained historical data including spatio-temporal attributes into the real world scope of space and time using spatio-temporal concept hierarchy.