• 한국전문물리치료학회지
• /
• 제26권2호
• /
• pp.1-7
• /
• 2019

Background: In previous studies, changes in postural alignment were found when the slope was changed during walking. Downhill walking straightens the trunk by shifting the line of gravity backward. Objects: This study investigated the effect of the downhill treadmill walking exercise (DTWE) on thoracic angle and thoracic erector spinae (TES) activation in subjects with thoracic kyphosis. Methods: A total of 20 subjects with thoracic kyphosis were recruited for this study. All the subjects performed the DTWE for 30 minutes. A surface EMG and 3D motion capture system were used to measure TES activation and thoracic angle before and after the DTWE. Paired t-tests were used to confirm the effect of the DTWE (p<.05). Results: Both the thoracic angle and TES activation had significantly increased after the DTWE compared to the baseline (p<.05). An increase in the thoracic angle indicates a decrease in kyphosis. Conclusion: The DTWE is effective for thoracic kyphosis patients as it decreases their kyphotic posture and increases the TES activation. Future longitudinal studies are required to investigate the long-term effects of the DTWE.

• 제어로봇시스템학회논문지
• /
• 제20권10호
• /
• pp.1057-1062
• /
• 2014

This paper proposes a tip-over detection method for a mobile robot using a support inscribed circle defined as an inscribed circle of a support polygon. A support polygon defined by the contact points between the robot and the terrain is often used to analyze the tip-over. For a robot moving on uneven terrain, if the intersection between the extended line of gravity from the robot's COG and the terrain is inside the support polygon, tip-over will not occur. On the contrary, if the intersection is outside, tip-over will occur. The terrain is detected by using an RGB-D sensor. The terrain is locally modeled as a plane, and thus the normal vector can be obtained at each point on the terrain. The support polygon and the terrain's normal vector are used to detect tip-over. However, tip-over cannot be detected in advance since the support polygon is determined depending on the orientation of the robot. Thus, the support polygon is approximated as its inscribed circle to detect the tip-over regardless of the robot's orientation. To verify the effectiveness of the proposed method, the experiments are carried out using a 4-wheeled robot, ERP-42, with the Xtion RGB-D sensor.

• 정보보호학회논문지
• /
• 제11권5호
• /
• pp.53-62
• /
• 2001

개인 컴퓨터와 네트워크의 급속한 보급 및 발전된 보안기술은 기존 투표형식의 많은 문제점들을 보완하면서 편리하고 안전한 전자투표의 비중을 증대시키고 있다. 그러나 이러한 비중의 증대에도 불구하고, 많은 취약점들이 산재해있다. 특히, 투표자의 익명성과 투표결과의 정확성을 보장하는 문제는 전자투표 프로토콜이 실제 응용될 수 있는가를 판단하는 중요한 요소가 아닐 수 없다. 또한 투표권의 매매와 같은 문제들은 아직도 해결해야 될 과제로 남아 있다. 본 논문에서는 안전한 전자투표를 설계하기 위하여 고려해야 할 사항들을 살펴보고, [1]에서 발표되었던 전자투표 프로토콜의 취약점과 개선 방안을 제시한다. 개선된 프로토콜은 [1]에서 제시된 장점들을 유지하면서, 선거관리자와 집계자의 공모에 의한 투표권자의 익명성 훼손을 막고, 불법적인 선거개입을 원천적으로 봉쇄하도록 설계되었다.

• 한국정밀공학회지
• /
• 제19권2호
• /
• pp.114-125
• /
• 2002

As semi-solid forging (SSF) is compared with conventional easting such as gravity die-easting and squeeze casting, the product without inner defects can be obtained from semi-solid forming and globular microstructure as well. Generally speaking. SSF consists of reheating, forging, ejecting precesses. In the reheating process, the materials are heated up to the temperature between the solidus and liquidus line at which the materials exists in the form of liquid-solid mixture. The process variables such as reheating time, reheating temperature, reheating holding time, and induction heating power have much effect on the quality of the reheated billets. It is difficult to consider all the variables at the same time when predicting the quality. In this paper, Taguchi method, regression analysis and neural network were applied to analyze the relationship between processing conditions and solid fraction. A356 alloy was used for the present study, and the learning data were extracted by the reheating experiments. Results by neural network were on good agreement with those by experiment. Polynominal regression analysis was formulated by using the test data from neural network. Optimum processing condition was calculated to minimize the grain size, solid fraction standard deviation, otherwise, to maximize the specimen temperature average. In this time, discussion is liven about reheating process of row material and results are presented with regard to accurate process variables for proper solid fraction, specimen temperature and grain size.

• Asian-Australasian Journal of Animal Sciences
• /
• 제25권7호
• /
• pp.1015-1020
• /
• 2012

An experiment was conducted to evaluate the effects of bacteriophage supplementation on egg performance, egg quality, excreta microflora, and moisture content in laying hens. A total of 288 Hy-line brown commercial laying hens (36-wk-old) were randomly allotted to 4 treatments in this 6-wk trial and dietary treatments included: i) CON, basal diet; ii) T1, CON+0.020% bacteriophage; iii) T2, CON+0.035% bacteriophage; iv) T3, CON+0.050% bacteriophage. There were 6 replicates for each treatment with 6 adjacent cages (2 hens/cage). Laying hens in T2 and T3 treatments had higher (p<0.05) egg production than those in CON and T1 treatments during wk 0 to 3. In addition, egg production in T1, T2, and T3 treatments was increased (p<0.05) compared with that in CON treatment during wk 4 to 6. At wk 4 and 5, birds in T2 group had higher (p<0.05) HU than those in CON. In addition, at wk 5 and 6, HU in birds fed T1 and T3 diets was greater (p<0.05) than those fed CON diet. E. coli and Salmonella spp. concentrations in excreta were decreased (p<0.05) by T1, T2, and T3 treatments. However, egg weight, egg shell color, yolk height, yolk color unit, egg shell strength, egg shell thickness, egg gravity, and excreta moisture content were not influenced by dietary treatments during the entire experimental period. In conclusion, bacteriophage supplementation has beneficial effects on egg production, egg albumen, and excreta microflora concentration in laying hens.

• Steel and Composite Structures
• /
• 제22권1호
• /
• pp.113-139
• /
• 2016

The nonlinear seismic responses of steel buildings with perimeter moment resisting frames (PMRF) and interior gravity frames (IGF) are estimated, modeling the interior connections first as perfectly pinned (PPC), and then as partially restrained (PRC). Two 3D steel building models, twenty strong motions and three levels of the PRC rigidity, which are represented by the Richard Model and the Beam Line Theory, are considered. The RUAUMOKO Computer Program is used for the required time history nonlinear dynamic analysis. The responses can be significantly reduced when interior connections are considered as PRC, confirming what observed in experimental investigations. The reduction significantly varies with the strong motion, story, model, structural deformation, response parameter, and location of the structural element. The reduction is larger for global than for local response parameters; average reductions larger than 30% are observed for shears and displacements while they are about 20% for bending moments. The reduction is much larger for medium- than for low-rise buildings indicating a considerable influence of the structural complexity. It can be concluded that, the effect of the dissipated energy at PRC should not be neglected. Even for connections with relative small stiffness, which are usually idealized as PPC, the reduction can be significant. Thus, PRC can be used at IGF of steel buildings with PMRF to get more economical construction, to reduce the seismic response and to make steel building more seismic load tolerant. Much more research is needed to consider other aspects of the problem to reach more general conclusions.

• 한국산림과학회지
• /
• 제34권1호
• /
• pp.1-14
• /
• 1977

지리산(智異山) 일대(一帶)에 생육(生育)되고 있는 잣나무집단(集團)의 변이(變異)를 구명(究明)하기 위해 수형(樹形), 침엽(針葉), 자엽(子葉), 종자(種子), 묘목성장(苗木成長)의 특성(特性)을 조사하였다. 두개 집단(集團)을 비교(比較) 검토(檢討)하였던 바 그 결과(結果)를 요약(要約)하면 다음과 같다. 1. 침엽(針葉)의 엽장(葉長), 거치밀도(鋸齒密度), 종자충실율(種子充實率), 종자장(種子長), 종자후(種子厚), 자엽장(子葉長), 자엽폭(子葉幅), 자엽(子葉)의 기공선수(氣孔線數)와 묘고성장(苗高成長)에 있어서는 집단(集團), 개체간(個體間)에 유의차(有意差)를 인정(認定)할 수 있었다. 2. 수목(樹木)의 역지각(力枝角)과 목재(木材)의 비중(比重), 자엽(子葉)의 수지구수(樹脂溝數)의 형질(形質)에 있어서는 집단간(集團間)에 유의차(有意差)가 인정(認定)되었다. 3. 침엽(針葉)의 기공선수(氣孔線數), 종자폭(種子幅), 종자중량(種子重量), 자엽(子葉)의 거치밀도(鋸齒密度), 자엽수(子葉數)의 형질(形質)은 개체간(個體間)에 유의차(有意差)를 인정(認定)할 수 있었다. 4. 침엽(針葉)의 수지구(樹脂溝)는 집단(集團), 개체간(個體間) 모두 3개(個)의 주수지구(主樹脂溝)만 발달(發達)하여 변이폭(變異幅)은 인정(認定)할 수 없었다. 그리고 수간형(樹幹型)은 두 집단(集團) 모두 통직성(通直性)을 나타내었다. 5. 침엽(針葉)과 자엽(子葉) 형질(形質)의 변이계수(變異係數)는 대체로 자엽(子葉)의 것이 큰 경향(傾向)을 나타내었다.

• 천문학회보
• /
• 제36권1호
• /
• pp.37.2-37.2
• /
• 2011

Our previous study on tiny pores (R < 2") observed by HINODE/Solar Optical Telescope (SOT) revealed that the plasma in the pores at the photosphere is always moving down and the pores are surrounded by the strong downward motions (highly red-shifted) of neighboring granulations. From this study, we speculated that the flow motions above the pore should be related with the motions at the photosphere, since the pore is strong magnetic field region. Meanwhile, SNU and KASI installed Fast Imaging Solar Spectrograph (FISS) in the Cude room of the 1.6 m New Solar Telescope (NST) at Big Bear Solar Observatory. FISS is a unique system that can do imaging of H-alpha and Ca II 8542 band simultaneously, which is quite suitable for studying of dynamics of chromosphere. To get some clue on the relationship between the photospheric and low-chromospheric motions at the pore region, we took a coordinate observation with NST/FISS and Hinode/SOT for new emerging active region (AR11117) on October 26, 2010. In the observed region, we could find two tiny pores and two small magnetic islands (SMIs), which have similar magnetic flux with the pores but does not look dark. Magnetic flux density and Doppler velocities at the photosphere are estimated by applying the center-of-gravity (COG) method to the HINODE/spectropolarimeter (SP) data. The line-of-sight motions above the photosphere are determined by adopting the bisector method to the wing spectra of Ha and CaII 8542 lines. As results, we found the followings. (1) There are upflow motion on the pores and downflow motion on the SMIs. (2) Towards the CaII 8542 line center, upflow motion decrease and turn to downward motion in pores, while the speed of down flow motion increases in the SMIs. (3) There is oscillating motion above pores and the SMIs, and this motion keep its pattern along the height. (4) As height increase, there is a general tendency of the speed shift to downward on pores and the SMIs. This is more clearly seen on the other regions of stronger magnetic field. In this talk, we will present preliminary understanding of the coupling of pore dynamics between the photosphere and the low-chromosphere.

• 지구물리와물리탐사
• /
• 제26권2호
• /
• pp.77-83
• /
• 2023

이 논문에서는 타원 기둥 형태의 이상체에 의한 자력 벡터와 자력 변화율 텐서 반응식을 유도하였다. 화성암 관입이나 킴벌라이트 구조 등은 축 대칭성을 가지면서 주향 방향과 수직한 방향의 반지름이 서로 다른 타원 기둥 형태를 가지는 경우가 많다. 이런 타원 기둥의 자력 반응은 이전 논문에서 유도한 중력 변화율 텐서에 자화 방향에 대한 정보를 포함시킨 포아송 관계식을 이용하여 유도하였다. 타원 기둥의 자력 변화율 텐서는 벡터 자력을 미분하여 유도하는데 삼중 적분으로 표현되는 타원 기둥의 인력 퍼텐셜을 각 축방향으로 3회 미분한 총 10개의 삼중 미분 함수를 구하는 것과 동일하다. 미분과 적분의 순서는 바꾸는 것이 가능하므로 결과적으로 자력 변화율 텐서는 타원 기둥의 인력 퍼텐셜을 3회 미분한 후, 깊이 방향으로 적분하고 나머지 이중 적분은 복소 평면에서 타원 기둥의 단면을 폐곡선으로 하는 경로를 따라 선적분으로 변환하여 유도된다. 이 논문에서 복소 평면에서 선적분으로 유도한 자력 및 자력 변화율 텐서 반응식은 립쉬츠-한켈 적분으로 유도한 원기둥의 자력 및 자력 변화율 텐서 반응식과 완벽하게 일치함을 보였다.

• 재활복지공학회논문지
• /
• 제9권2호
• /
• pp.161-168
• /
• 2015

본 논문은 자체 개발한 관성측정장치의 가속도, 각속도, 지자기계 데이터를 이용하여 보행거리를 측정하는 시스템 개발에 관한 것이다. 관성센서들의 오프셋 및 이득 오차를 최소화하기 위하여 9축의 자유도를 갖는 지그를 제작하였으며, 이를 이용하여 캘리브레이션을 수행하였다. 보행거리의 정확한 측정을 위하여, 기울기 하강법을 이용하여 가속도계의 중력성분 제거 및 보행패턴 분석을 통한 드리프트 성분을 제거하였다. 최종적으로 보정된 가속도 데이터의 이중적분을 통하여 보행거리를 측정하였다. 시스템의 성능 평가를 위하여, 실내 직선 10m 직선 보행에 대하여 캘리브레이션 전, 후 오차 개선 비율를 비교하였으며, 간단한 보행에 대해 Vicon과의 비교 실험을 수행하였다. 직선 보행에 대해서는 x, y, z축 각각에 대하여 $31.4{\pm}14.38%$(mean${\pm}$S.D.), $78.64{\pm}10.84%$ 및 $69.71{\pm}26.25%$ 개선이 되었음을 확인하였으며, Vicon과의 비교 실험 결과 x, y, z축 각각에 대하여 0.1m, 0.16m, 0.12m의 오차를 얻을 수 있었다.