• 한국재료학회지
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• 제21권1호
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• pp.28-33
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• 2011

This paper describes the fabrication of AlN thin films containing iron and iron nitride particles, and the magnetic and electrical properties of such films. Fe-N-Al alloy films were deposited in Ar and $N_2$ mixtures at ambient temperature using Fe/Al composite targets in a two-facing-target DC sputtering system. X-ray diffraction results showed that the Fe-N-Al films were amorphous, and after annealing for 5 h both AlN and bcc-Fe/bct-$FeN_x$ phases appeared. Structure changes in the $FeN_x$ phases were explained in terms of occupied nitrogen atoms. Electron diffraction and transmission electron microscopy observations revealed that iron and iron nitride particles were randomly dispersed in annealed AlN films. The grain size of magnetic particles ranged from 5 to 20 nm in diameter depending on annealing conditions. The saturation magnetization as a function of the annealing time for the $Fe_{55}N_{20}Al_{25}$ films when annealed at 573, 773 and 873 K. At these temperatures, the amount of iron/iron nitride particles increased with increasing annealing time. An increase in the saturation magnetization is explained qualitatively in terms of the amount of such magnetic particles in the film. The resistivity increased monotonously with decreasing Fe content, being consistent with randomly dispersed iron/iron nitride particles in the AlN film. The coercive force was evaluated to be larger than $6.4{\times}10^3Am^{-1}$ (80 Oe). This large value is ascribed to a residual stress restrained in the ferromagnetic particles, which is considered to be related to the present preparation process.

• 전기전자학회논문지
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• 제20권4호
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• pp.392-397
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• 2016

본 논문에서는 투명 전극용 ITO(Indium Tin Oxide) 박막의 성막 조건을 알아내기 위하여 DC(Direct Current) 마그네트론 스퍼터를 사용해 증착된 ITO 박막의 특성을 분석하였다. 실험 조건은 1~3[mTorr] 분위기압으로 조절하고 인가전압은 260~330[V]로 10[V]씩 스텝을 주어 실험을 진행하였다. 증착된 박막의 투과율, 굴절률 및 표면과 단면 형상을 자외선-가시광선 분광광도계, 타원편광분석기와 주사전자현미경으로 측정하였다. ITO 성막 조건 1~2[mTorr] 분위기압에서 300[V] 정도의 전압이 투과율이 90[%] 이상으로 우수하고 굴절률이 2이상 이였다. 따라서 높은 투명 전도성 전극을 만들기에 적절한 조건임을 확인하였다.

• International Journal of Internet, Broadcasting and Communication
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• 제9권4호
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• pp.38-43
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• 2017

Sensor Networks (WSNs) can be defined as a self-configured and infrastructure-less wireless networks to monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, motion or pollutants and to cooperatively pass their data through the network to a main location or base-station where the data can be observed and analyzed. Typically a wireless sensor network contains hundreds of thousands of sensor nodes. The sensor nodes can communicate among themselves using radio signals. A wireless sensor node is equipped with sensing and computing devices, radio transceivers and power components. The individual nodes in a wireless sensor network (WSN) are inherently resource constrained: they have limited processing speed, storage capacity, communication bandwidth and limited-battery power. At present time, most of the research on WSNs has concentrated on the design of energy- and computationally efficient algorithms and protocols In order to extend the network life-time, in this paper we are looking into a routing protocol, especially LEACH and LEACH-related protocol. LEACH protocol is a representative routing protocol and improves overall network energy efficiency by allowing all nodes to be selected to the cluster head evenly once in a periodic manner. In LEACH, in case of movement of sensor nodes, there is a problem that the data transmission success rate decreases. In order to overcome LEACH's nodes movements, LEACH-Mobile protocol had proposed. But energy consumption increased because it consumes more energy to recognize which nodes moves and re-transfer data. In this paper we propose the new routing protocol considering nodes' mobility. In order to simulate the proposed protocol, we make a scenario, nodes' movements randomly and compared with the LEACH-Mobile protocol.

• 정보처리학회논문지B
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• 제13B권1호
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• pp.15-20
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• 2006

이 논문은 컴퓨터 게임을 위한 물리 엔진의 성능 향상 및 이를 적용한 지능적인 게임 캐릭터에 관한 연구를 서술한다. 물리적 상황을 자동으로 인식하는 알고리즘으로는 Momentum back-propagation을 적용하였다. 또한 우리는 각 상황에 따른 적분 방식의 실험 결과를 제시한다. 실험을 위하여 Euler Method, Improved Euler Method, 및 Runge-kutta Method의 세 가지의 적분 방식을 적용하였다. 각 적분 방식의 실험 결과에서 충돌이 없는 상황에서는 Euler Method가 최적의 성능을 보여주었다. 또한 충돌 상황에서는 세 가지 방식이 모두 비슷한 성능을 보여주었지만, Runge-kutta Method가 최적의 정확도를 보여주었다. 물리 상황인식에 대한 실험결과에서는 입력 층과 출력 층이 고정된 상태에서 은닉 층이 3일 때 가장 좋은 성능을 보여주었고, 또한 학습횟수가 30000일 때 최적의 성능을 보여주었다. 앞으로 우리는 다른 장르의 게임에 이러한 물리적 컨텍스트(context)를 인식하는 연구를 진행할 것이며 또한 전체 게임의 성능을 증가할 수 있도록 M-BP이외의 인식 알고리즘을 적용할 것이다.

• 한국세라믹학회지
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• 제53권2호
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• pp.162-166
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• 2016

0.75BF-0.25BT ceramics were prepared by sintering at $980-1040^{\circ}C$ in air or under atmosphere powder. A sample with 1 mole %-excess $Bi_2O_3$ was also prepared to compensate for $Bi_2O_3$-evaporation. Physical and piezoelectric properties of these three samples were compared. When the sintering temperature increased from $980^{\circ}C$ to $1040^{\circ}C$, the density of the sample sintered in air decreased continuously due to Bi-evaporation. Due to the suppression of Bi-evaporation, the sample sintered under atmosphere powder had a higher density at sintering temperatures above $1000^{\circ}C$ than did the sample sintered in air. The addition of 1 mole %-excess $Bi_2O_3$ successfully compensated for Bi-evaporation and kept the density at the higher value until $1020^{\circ}C$. Grain size increased continuously when the sintering temperature increased from 980 to $1040^{\circ}C$, irrespective of the sintering atmosphere. When the sintering temperature increased, the piezoelectric constant ($d_{33}$) and the electromechanical coupling factor ($k_p$) increased for all samples. The sample with 1 mole % excess-$Bi_2O_3$ showed the highest density and the best piezoelectric properties at sintering temperature of $1020^{\circ}C$.

• 전자공학회논문지CI
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• 제46권1호
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• pp.128-135
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• 2009

동영상에서 시공간상 일정한 위상을 갖는 윤곽선을 정합시켜 물리적 공간에서의 동일한 위치를 추적하는 방법은 명암이 일정한 윤곽선을 정합시키거나 일정한 명암을 전제로 추적하는 방법에 비해 정확성이 높고 조명조건에 대해 안정된 특성이 있다. 본 논문에서는 이러한 성질을 이용하여 조명변화와 노이즈에 강인하게 카메라의 움직임을 추정하는 기법을 소개한다. 우선, 가버 필터뱅크를 사용하여 공간적으로 여과된 연속영상으로부터 계산된 위상의 크기를 기반으로 필터의 방향과 수직인 곳의 광류를 구한 후, 최소제곱법을 적용하여 어파인 모델에 상응하는 카메라의 움직임 파라미터를 구한다. 실험을 통하여 이러한 방법은 조명조건의 변화를 야기하는 디스플레이 기기를 피사체로 하여 카메라의 위치변화를 추정하는 방식의 영상기반 포인팅 디바이스에도 적용될 수 있음을 보인다.

• 복식
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• 제34권
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• pp.109-120
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• 1997

The conservation of collections in muse-ums is an important aspect for our her-itage. The control of museum environment is a vital factor in the preservation of cool-lections. Inappropriate or fluctuating envi-ronmental conditions can cause irreparable damage to works of arts. In this research we investigated the ac-tual conditions of museum environment for old testiles using questionnaire and mea-sured dye fasing of old textiles on exhibi-tion for 2 months in a university museum the major results are as follows: 1. The control of temperature and rela-tive humidity is a vital factors I the preservation of old textiles in museum generally acceptable temperature and rel-ative humidity standards for old textiles are 18-23$^{\circ}C$ and 50-65% R. H and light level for textiles on exhibition should be limited to 30-50 lux. 2, In university museums the limate control system in exhibition and storage area is in an early stage. Therefore to minimize the deterioration of old textiles the best method of controlling the envi-ronment is to have centralized climate control system in sorage area as well as in display area. 3. Conservator is needed to maintain collections scientifically. Only professional conservator by combining scientific tech-nical and artistic training has the exper-tise needed to maintain the physical in-tegrity of old textiles. In order to solve the inferior environment of museums the staff should recognize the importance of the condition of exhibition and storage. 4. Old textiles are susceptible to damage by light and associated heat. Dyed textiles which have been exhibited under the light without any UV filter were faded notice-ably within two months of exhibition. Light levels for textiles on exhibition should be limited to 30-50 lux. It is de-sirable to use special light source that can absorb UV. and UV filter is also recom-mended to reduce photodegradation of old textiles.

• Journal of Preventive Medicine and Public Health
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• 제24권3호
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• pp.305-313
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• 1991

In order to investigate industrial fatigue due to visual display terminal (VDT) work of banking operations the questionnaire survey for subjective symptoms of fatigue was carried out on 470 bank clerks who had been engaged in VDT work for various length of work hours. The questionnaires comprised three groups of 10 items each, representing dullness and sleepiness (level of cerebral activation), difficulty in concentration (level of motivation) and bodily projection of fatigue. The results were as follows : 1. Of the 30 items of questionnaires, the highest percentage was accounted for by 'eye strain' (51.5% ), followed by 'feel stiffness in the neck or the shoulders'(33.4%), 'feel a pain in the low back'(26.8%), 'whole body feels tired'(19.6%) and 'feel headache'(17.9%) in the order of sequence. 2. The average weighted score for the first group of questionnaire items (dullness and sleepiness) was the largest among three groups and was followed by 'the third cup (bodily projection of fatigue) and the second item group (difficulty in concentration) in the order of sequence, suggesting the heavier mental stress of VDT work in banking operations rather than physical burden. 3. In terms of the age and sex of workers, work duration and VDT work percentage, the difference in average weighted score was noted only between sex, the score of female being larger than that of male. 4. The complaint rates of subjective symptoms showed close associations with the subjective optimums of room temperature, ventilation, illumination and noise level. 5. The significant correlation was showed between age, work duration and item of 'whole body feels tired', between VDT work percentage and items of 'eye strain' and 'feel stiffness in the neck or shoulders' and between all items of subjective symptoms.

• 지역사회간호학회지
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• 제19권1호
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• pp.57-65
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• 2008

Purpose: The purpose of this study is to assess the priorities of health promotion for older adults in the rural community. The study attempts to display demographic characteristics subjective health status and chronic diseases status of the older adults. Methods: We surveyed 384 senior residents in a community via face-to-face interviews in their homes, who were selected by proportional random sampling. We analysed the frequency, multiple responses and $X^2$ by SPSS 12.0K. Results: The mean of subjective health status was $54.04{\pm}21.69$ with a maximum of 100. Our study found that the high priorities in health promotion for older adults were prevention and management of hypertension and diabetes, strengthening of joint and muscles, cancer screening and physical exercise. Prevention of depression and social activities were low priorities. Strengthening of joints and muscles was a high priority among women while smoking cessation and social activities were high priorities of men. Conclusion: In conclusion, health promotion priorities of older adults differed by gender and subjective health status. Disease-related priorities received more attention than psycho-social health priorities. This study suggests comparing the priorities regionally and nationally.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.304.1-304.1
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• 2014

Flat-panel displays have been growing as an essential everyday product in the current information/communication ages in the unprecedented speed. The forward-coming applications require light-weightness, higher speed, higher resolution, and lower power consumption, along with the relevant cost. Such specifications demand for a new concept-based materials and applications, unlike Si-based technologies, such as amorphous Si and polycrystalline Si thin film transistors. Since the introduction of the first concept on the oxide-based thin film transistors by Hosono et al., amorphous oxide thin film transistors have been gaining academic/industrial interest, owing to the facile synthesis and reproducible processing despite of a couple of shortcomings. The current work places its main emphasis on the binary oxides composed of ZnO and SnO2. RF sputtering was applied to the fabrication of amorphous oxide thin film devices, in the form of bottom-gated structures involving highly-doped Si wafers as gate materials and thermal oxide (SiO2) as gate dielectrics. The physical/chemical features were characterized using atomic force microscopy for surface morphology, spectroscopic ellipsometry for optical parameters, X-ray diffraction for crystallinity, and X-ray photoelectron spectroscopy for identification of chemical states. The combined characterizations on Zn-Sn-O thin films are discussed in comparison with the device performance based on thin film transistors involving Zn-Sn-O thin films as channel materials, with the aim to optimizing high-performance thin film transistors.