• 한국안전학회지
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• 제21권2호
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• pp.70-79
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• 2006

many plumbing system are needed in the ceiling of the building as it becomes advanced more and more. This leads to make effective space between ceiling level and slab less. Also, piping system is not suitably arranged and operated if it is bent around the columns which they are a lot. But this system can be more effective if it passes through the columns directly. Most people think that those columns should not be damaged with such as holes. But actually this is existed in a hotel building in switzerland. This study is to fing out how much capacity the columns become damaged and low using model size of $20cm{\times}30cm$ rectangular section, and 160cm long, in the structural test. it's compressive strength is focused on $240kg/cm^{2}$ design strength, commonly used in korea. Compressive test for them was done at Hanyang University using UTM one thousand tone(1000t) capacity. Variable numbers for the study are one hole of dia 3cm with distance 20cm or 40cm, two holes of dia 3cm with 20cm and 40cm distance, one hole of dia 5cm with distance 20cm and 40cm, two holes of dia 5cm with 20cm and 40cm distance, me eccentric hole with 20cm and 40cm distance, Normal(without hole). two test specimens of each variable are made for the test. ED5H20 capacity was 16.7% decreased, compared to normal one. While ED5H40 distant 40cm from the end of column top showed 19.5% capacity decrease, compared to normal one. Strain of ED5H20 diameter 5cm, in distance of 20cm form the top of the column was less 5% than the one of diameter 3cm. Finally, conclusions are that in case of hole diameter 3cm, located at 20cm from the end of the column top, capacity was decreased down to 3, percent only compared to the same diameter hole with 20cm distant from the end of it.

• 한국생산제조학회지
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• 제7권1호
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• pp.9-21
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• 1998

This paper a new solution approach to moving obstacle avoidance problem of a mobile robot. A new concept avoidability measure (AVM) is defined to describe the state of a pair of a robot and an obstacle regarding the collision between them. As an AVM, virtual distance function (VDF), is derived as a function of the distance from the obstacle to the robot and outward speed of the obstacle relative to the robot. By keeping the virtual distance above some positive limit value, the robot avoids the obstacle. In terms of the VDF ,an artificial potential field is constructed to repel the robot away from the obstacle and to attract the robot toward a goal location. At every sampling time, the artificial potential field is updated and the force driving the robot is derived from the gradient of the artificial potential field. The suggested algorithm drives the robot to avoid moving obstacles in real time. Since the algorithm considers the mobility of the obstacle as well as the distance, it is effective for moving obstacle avoidance. Some simulation studies show the effectiveness of the proposed approach.

• 한국생산제조학회지
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• 제22권3호
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• pp.421-428
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• 2013

The current vibration reduction methods for positioning systems lead to either complicated motion or the need for additional hardware when the positioning systems carry out frequent short-distance movements. This paper proposes a simple yet efficient vibration reduction method for positioning systems subjected to frequent short-distance movements. The essence of the proposed method is the trapezoidal or triangular velocity profiles, whose acceleration/deceleration rates are designed to be related to the natural frequency of concern. The combined use of the proposed method and the input shaping method is also proposed for the possible application to multi-mode systems. Experiments are performed to validate the proposed method. The simulation and experiments prove that the proposed method is of great use for residual vibration reduction in positioning systems subjected to frequent short-distance movement.

• 한국농공학회지
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• 제17권3호
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• pp.3872-3877
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• 1975

This study was conducted to examine the effects of the change of cap hole diameter and pressure on the travelling distance and the sprayed particle size for the medium range nozzle. The results of this study are summarized as follows; 1) The effective travelling distance was about from 1 meter to 8 meters and centro-position of the travelling distance was about 3 or 5 meters. 2) Main effect of change of cap hole diameter for the travelling distance was a slight convex quadratic curve. 3) Main effect of change of pressure increased linearly, its increasing rate about 1.6 was large. 4) Sizes of sprayed particles were less than 250${\mu}$ generally and the sizes decreased according to the increasing of travelling distance. 5) Changes of diameter of sprayed particles by cap hole diameter increased in accordance with increasing of cap hole diameter. 6) Changes of diameter of sprayed particles by the groove depth of swirl plate was very slight.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.268-272
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• 1996

Error correction effect for maladjusted stereo cameras with calibrated pixel distance parameter is presented. The camera calibration is a necessary procedure for stereo vision-based depth computation. Intra and extra parameters should be obtain to determine the relation between image and world coordination through experiment. One difficulty is in camera alignment for parallel installation: placing two CCD arrays in a plane. No effective methods for such alignment have been presented before. Some amount of depth error caused from such non-parallel installation of cameras is inevitable. If the pixel distance parameter which is one of intra parameter is calibrated with known points, such error can be compensated in some amount. Such error compensation effect with the calibrated pixel distance parameter is demonstrated with some experimental results.

• 말소리와 음성과학
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• 제1권3호
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• pp.109-115
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• 2009

Many isolated word recognition systems may generate non-similar words for recognition candidates because they use only acoustic information. In this paper, we investigate several techniques which can exclude non-similar words from N-best candidate words by applying Levenstein distance measure. At first, word distance method based on phone and syllable distances are considered. These methods use just Levenstein distance on phones or double Levenstein distance algorithm on syllables of candidates. Next, word similarity approaches are presented that they use characters' position information of word candidates. Each character's position is labeled to inserted, deleted, and correct position after alignment between source and target string. The word similarities are obtained from characters' positional probabilities which mean the frequency ratio of the same characters' observations on the position. From experimental results, we can find that the proposed methods are effective for removing non-similar words without loss of system performance from the N-best recognition candidates of the systems.

• Smart Structures and Systems
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• 제6권9호
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• pp.991-1005
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• 2010

The key to detecting damage to civil engineering structures is to find an effective damage indicator. The damage indicator should promptly reveal the location of the damage and accurately identify the state of the structure. We propose to use the distance measures of low-order AR models as a novel damage indicator. The AR model has been applied to parameterize dynamical responses, typically the acceleration response. The premise of this approach is that the distance between the models, fitting the dynamical responses from damaged and undamaged structures, may be correlated with the information about the damage, including its location and severity. Distance measures have been widely used in speech recognition. However, they have rarely been applied to civil engineering structures. This research attempts to improve on the distance measures that have been studied so far. The effect of varying the data length, number of parameters, and other factors was carefully studied.

• 제어로봇시스템학회논문지
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• 제17권5호
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• pp.499-504
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• 2011

In this paper, we suggest a method for discretized frequency modulations of ultrasonic signals. A continuous sweep of frequency modulation signals can be modelled with fine levels of discretization. If the ultrasound signals are modulated with monotonically decreasing frequencies, then the cross-correlation between an emitted signal and received signal can be used to identify the distance of multiple target objects. For the discretized frequency synthesis, CF ultrasounds with different frequencies are serially ordered. The auto-correlation test with the signal shows effective results for distance estimation. The discretized frequency syntheses have better distance resolution than CF ultrasound signals and the resolution depends on the number of the combined ultrasound frequencies.

• 한국측량학회지
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• 제8권1호
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• pp.51-56
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• 1990

최근, 광파거리측량기(EDM)가 트래버스측량과 3변측량에 널리 활용되고 있는 추세에 비추어, 본 연구에서는 Electronic Total Stations (Set 3)을 이용, 개합 트래터스망을 엄밀히 조정하기 위하여 측각과 측거를 고려한 동시조정법으로 엄밀조정을 행하였으며, 또한 관측거리 및 배각수에 따라 측각에 발생하는 각종 우연오차를 검토해 보았다. 그리고 본 동시조정법과 컴파스측정 및 트랜싯트법칙을 비교 검토한 결과, 측각과 측거를 고려한 동시조정법이 정학도가 가장 좋아 타조정법에 비해 실용성 및 적용의 타당성이 입증되었다.

• 한국콘텐츠학회논문지
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• 제19권10호
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• pp.593-606
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• 2019

본 연구는 해석수준이론을 바탕으로 리타게팅 광고의 특성에 맞는 효과적인 메시지 전략을 검토하고자 했다. 먼저 주로 사람들간에 적용되어 온 사회적 거리가 온라인 사이트 유형에 적용가능한지 확인한 후 사이트 유형별 사회적 거리의 효과를 확인하였다. 나아가 사회적 거리와 시간적 거리가 복합적으로 작동할 때 소비자들의 사고수준은 어느 방향으로 활성화되는지, 그에 따른 메시지 효과가 어떻게 달라지는지를 분석하였다. 분석결과 웹사이트 유형별 사회적 거리와 메시지의 해석수준은 기존의 CLT 연구와 일치하였다. 그러나 시간적 거리, 사회적 거리, 그리고 메시지의 해석수준까지 일치할 경우(근미래${\times}$근사회${\times}$구체 메시지 혹은 원미래${\times}$원사회${\times}$추상메시지)에만 광고효과가 더 높을 거라는 주장은 부분적으로만 검증되었다. 또한 두 차원의 거리는 하나의 심리적 공간아래 통합되어 두 심리적 거리 중 하나만이라도 멀면 상위수준으로 사고하게 되기 때문에 두 심리적 거리가 모두 먼 경우와 차이가 없다는 기존의 입장도 기각되었다. 오히려 시간과 사회적 거리가 불일치할 경우, 두 차원 중 메시지의 해석수준이 사회적 거리와 일치할 때 더 효과적인 것으로 나타나 심리적 거리의 영향력이 종류에 따라 다를 수 있다는 추론을 가능하게 했다.