• 대한기계학회논문집A
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• 제21권11호
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• pp.1950-1956
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• 1997

An engineering goal in vibration and noise professionals is to develope quiet machines at the preliminary design stage, and various numerical techniques such as FEM, SEA or BEM are one of the schemes toward the goal. In this paper, the research has been focused on the sensitivity effect of mesh sizes for FEM application so that the optimum size of the mesh that leads to engineering solution within acceptable computing time could be generated. In order to evaluate the mesh size effect, three important parameters have been examined : natural frequencies, number of modes and driving point mobility. First, several lower modes including the fundamental frequency of a 2-D plate structure have been calculated as mesh size changes. Since theoretical values of natural frequencies for a simple structure are known, the deviation between the numerical and theoretical values is obtained as a function of mesh size. The result shows that the error is no longer decreased if the mesh size becomes a quarter wavelength or smaller than that. Second, the mesh size effect is also investigated for the number of modes. For the frequency band up to 1.4 kHz, the structure should have 38 modes in total. As the mesh size reaches to the quarter wavelength, the total count in modes approaches to the same values. Third, a mobility function at the driving point is compared between SEA and FEM result. In SEA application, the mobility function is determined by the modal density and the mass of the structure. It is independent of excitation frequencies. When the mobility function is calculated from a wavelength to one-tenth of it, the mobility becomes constant if the mesh becomes a quarter wavelength or smaller. We can conclude that dynamic parameters, such as eigenvalues, mode count, and mobility function, can be correctly estimated, while saving the computing burden, if a quarter wavelength (.lambda./4) mesh is used. Therefore, (.lambda./4) mesh is recommended in structural vibration analysis.

• 전자공학회논문지A
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• 제33A권10호
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• pp.123-129
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• 1996

LDD structure is widely accepted in fabricating short channel MOSFETs due to reduced short channel effect originated form lower drain edge electric field. However, modeling of the LDD device is troublesome because the analysis methods of LDD region known are either too complicated or inaccurate. To solve the problem, this paper presents a nonlinear resistance model for the LDD region based on teh fact that the electron mobility changes with positive gate bias because accumulation layer of electrons is formed at the surface of the LDD region. To prove the usefulness of the model, single source/drain and LDD nMOSFETs were fabricated with 0.35$\mu$m CMOS technolgoy. For the fabricated devices we have measured I$_{ds}$-V$_{gs}$ characteristics and compare them to the modeling resutls. First of all, we calculated channel and LDD region mobility from I$_{ds}$-V$_{gs}$ characteristics of 1050$\AA$ sidewall, 5$\mu$m channel length LDD NMOSFET. Then we MOSFET and found good agreement with experiments. Next, we use calculated channel and LDD region mobility to model I$_{ds}$-V$_{gs}$ characteristics of LDD mMOSFET with 1400 and 1750$\AA$ sidewall and 5$\mu$m channel length and obtained good agreement with experiment. The single source/drain device characteristic modeling results indicates that the cahnnel mobility obtained form our model in LDD device is accurate. In the meantime, we found that the LDD region mobility is governed by phonon and surface roughness scattering from electric field dependence of the mobility. The proposed model is useful in device and circuit simulation because it can model LDD device successfully even though it is mathematically simple.

• 감성과학
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• 제19권2호
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• pp.67-78
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• 2016

본 연구는 고령 운전자의 운전능력에 대한 주관적 평가와 객관적 수행, 이동성 및 주관적 안녕감 사이의 관련성을 살펴보기 위해 수행되었다. 고령 운전자들의 이동성과 주관적 안녕감은 설문조사 방법을 통해 측정하였다. 운전능력에 대한 주관적 평가는 다양한 운전 상황을 도식적으로 제시한 후 각 상황에서의 운전능력을 주관적으로 평정하게 하였고. 객관적 수행은 운전 시뮬레이션을 이용하여 측정하였다. 본 연구의 주요 결과를 요약하면 다음과 같다. 첫째, 고령 운전자의 운전능력에 대한 객관적 수행과 이동성 사이의 상관은 유의하지 않았던 반면, 주관적 평가와 이동성 사이의 상관은 정적으로 유의하였다. 그리고 이동성과 주관적 안녕감의 하위요인 중 삶의 만족, 긍정 정서와는 정적인 반면, 부정 정서와는 부적인 상관이 관찰되었다. 둘째, 고령 운전자의 운전능력에 주관적 평가가 높을수록 이동성 수준이 높았고, 이러한 높은 이동성은 다시 주관적 안녕감의 하위요인 중 삶의 만족과 긍정 정서를 정적으로 반면, 부정 정서는 부적으로 예측하였다. 본 연구의 결과들은 고령 운전자의 주관적 안녕감에는 객관적 운전수행보다는 운전 능력에 대한 스스로의 평가가 더 중요한 기여를 할 수 있다는 것을 시사한다.

• 토지주택연구
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• 제14권2호
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• pp.1-17
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• 2023

초고령사회 진입을 앞두고 우리나라는 노인인구의 급속한 증가로 노인주거 문제가 중요한 이슈로 떠오르고 있다. 특히, 노인인구의 살던 곳에서 노후 맞이하기(Aging in Place: AIP)는 노인복지의 지향점으로 꾸준히 제시되고 있다. 이에 본 연구는 2008-2020년 고령화연구패널 자료와 임의효과 로지스틱 회귀분석 모형을 사용하여 자녀와의 교류가 노인 주거이동에 미치는 영향을 실증 분석하였다. 연구 결과는 다음과 같다. 첫째, 자녀와의 교류가 수도권과 비수도권에 무관하게 노인인구의 주거이동을 촉진시킬 확률이 높다는 점을 발견하였다. 둘째, 연령이 증가할수록 자녀와의 교류는 노인인구의 주거이동을 더욱 촉진시키는 경향을 보였으나, 그 영향력은 연령과 변수에 따라 일정치 않게 나타났다. 셋째, 자녀와의 교류 변수들의 상호작용 효과를 통해 노인인구의 주거이동을 더욱 촉진시킬 가능성이 높아짐을 확인하였다. 본 연구는 자녀와의 교류가 노인인구의 주거 안정성을 증진 시켜 독립적인 정주 환경을 구성할 수 있는지, 즉 노인인구의 살던 곳에서 노후 맞이하기 측면에서 정책적 시사점을 제시한다.

• 한국건축시공학회지
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• 제24권4호
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• pp.483-494
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• 2024

본 연구는 노후 공공건축물에 모빌리티 기술을 접목하여 국민들의 이동 편의와 공공서비스 증진을 위한 방향으로 리뉴얼하는 모델을 개발하고, 실현 방향을 제고하기 위한 지원 방안 제안을 목적으로 한다. 본 연구의 주요 내용과 결과는 다음과 같다. 첫째, 모빌리티 기술을 접목한 공공건축물 리뉴얼에 필요한 기술적 고려 사항 및 평가 기준으로 리뉴얼 대상지를 선정하고, 선정된 대상지의 규모, 면적, 지구단위계획을 기반으로 필요한 모빌리티 기술을 분석하여 건축을 계획하였다. 둘째, 건축계획을 기반으로 예상 비용을 산정하고 모빌리티 기술을 반영할 때 필요한 재정적 지원 방안을 검토하였다. 셋째, 모빌리티 기술을 접목한 공공건축물 리뉴얼 개발에 필요한 건축기준 완화 방안을 제안하였다. 본 연구는 설계 기준 및 경험 부재로 인해 세부적인 공사비를 반영하지 못하였으며, 구체적인 운영 방식 및 실행된 사례가 없어서 구체적인 문제 파악이 어려운 점에 있어 한계가 있었다.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2006년도 춘계학술발표대회 논문집
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• pp.59-62
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• 2006

This design plan aims at the presentation of the representative character of Design Center by making a new image of the cafeteria that is located in the 1. floor. To create an ambience of intercommunication and relaxation, it must be set up the basic concepts like Mobility, Flexibility, Transparence and Color-Play. As the design solutions : - first of all the 360 grade reversible and removable dividers are installed around the 5 pillars - in accordance with the basic concepts Mobility and Flexibility the cubic form construct that plays not only a role of a kitchen, but also a role of a counter, is designed to be relocated at one's own. - the various kinds of seating module and the chill-out zone are introduced to bring out the functionality and the aestheticity simultaneaously - to make a contrasting image to the glass surface of the yellow-, orange- and red-colored dividers, the black chairs and tables are arranged in the middle.

• Journal of Computing Science and Engineering
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• 제5권1호
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• pp.19-31
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• 2011

In this paper, we propose two new routing schemes for double-layered peer-to-peer systems; a shorter-lower mobility routing scheme and a reverse path routing scheme. The shorter-lower mobility routing scheme first chooses shortest routing paths among possible routing paths and selects the path associated with the relay peer who has lower mobility to improve the reliability of the system. The reverse path routing scheme carries out unicasting (instead of multicasting) based on the reverse path information that can be obtained during the initial file search to further reduce network traffic. The experimental results showed that a double-layered peer-topeer system with the proposed hybrid scheme improved the reliability of the system about 1.5% over the hop count scheme and reduced network traffic by about 0.5% compared to the hop count scheme.

• 통상정보연구
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• 제9권2호
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• pp.87-101
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• 2007

This study developed seven assumptions to demonstrate the effect of personal innovation, social influences, service quality, mobility and accessibility on perceived usability, perceived convenience use and use intention using a technology acceptance model developed by Davis(1989), and the results are presented as follows: First, the assumption that personal innovation and service quality of mobile banking service will influence the perceived usability was adopted while the assumption that social influences will affect the perceived usability was rejected. Second, the assumption that mobility and accessibility of mobile banking services will influence the perceived convenient use was selected. Third, the assumption that the perceived usability of mobile banking service will influence use intention was rejected while the assumption that the convenient use will influence use intention was adopted. This study suggests that as personal innovation, service quality, mobility and accessibility have a significant influence on use of mobile banking, service providers should pay more attention to development of security programs and diversification of contents.

• Journal of Communications and Networks
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• 제7권2호
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• pp.171-177
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• 2005

This paper addresses mobility management (MM) requirements and framework for systems beyond IMT-2000 (SBI2K), based on the standardization works that has so far been done in ITU-T study group 19. We first identify the requirements for MM in SBI2K. Based on the identified MM requirements, we describe the MM framework for location management and handover management for SBI2K. We then review and analyze some of the existing IP-based MM protocols. From the analysis and comparison, we see that the existing MM schemes cannot meet all of the MM requirements for SBI2K. It is naturally concluded that further work is needed to enhance the available MM schemes SBI2K.

• Journal of Korean Neurosurgical Society
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• 제47권1호
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• pp.64-67
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• 2010

Although very rare, a few cases of intradural extramedullary (IDEM) spinal tumor migration have been reported since Tomimatsu first reported a mobile schwannoma of the cervical cord in 1974. Schwan noma is a neurogenic tumor which originates from nerve sheath that it is relatively well-marginated tumor with little attachment or adhesion to surrounding tissue. Mobility of tumor in spinal canal sometimes can result in negative exploration at the expected area. We found three interesting cases in which different tumor locations observed in repeated magnetic resonance image (MRI) findings. All tumors were intradural and extramedullary schwannoma. We reviewed the literature about moving tumor in the spine through PUBMED search.