• 한국군사과학기술학회지
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• 제13권6호
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• pp.951-957
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• 2010

An optimal path generation method considering the safety of UGV(Unmanned Ground Vehicle) is proposed and demonstrated through examples. Among various functions of UGV, real-time obstacle avoidance is a key issue to realize realistic scenario in FCS(Future Combat Systems). A two-dimensional narrow corridor environment is considered as a test field. For each step of UGV movement, two objectives are considered: One is to minimize the distance to the target and the other to maximize the distance to the nearest point of an obstacle. A weighted objective function is used in the optimization problem. Equality and inequality constraints are taken to secure the UGV's dynamics and safety. The weighting factors are controlled by a fuzzy controller which is constructed by a fuzzy rule set and membership functions. Simulations are performed for two cases. First the weighting factors are considered as constant values to understand the characteristics of the corresponding solutions and then as variables that are adjusted by the fuzzy controller. The results are satisfactory for realistic situations considered. The proposed optimal path generation with the fuzzy control is expected to be well applicable to real environment.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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• pp.496-500
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• 1998

Not merely running at the designated constant speed as the classical cruise control, the adaptive cruise control (ACC) maintains safe headway distance when the front is blocked by other vehicles. One of the most essential part of ACC System is the range sensor which can measure the position and speed of all objects in front continuously, ignore all irrelevant objects, distinguish vehicles in different lanes and lock on to the closest vehicle in the same lane. In this paper, the hierarchical object recognition algorithm (HORA) is proposed to process raw scanning laser data and acquire valid distance to target vehicle. HORA contains two principal concepts. First, the concept of life quantifies the reliability of range data to filter off the spurious detection and preserve the missing target position. Second, the concept of conformation checks the mobility of each obstacle and tracks the position shift. To estimate and predict the vehicle position Kalman filter is used. Repeatedly updated covariance matrix determines the bound of valid data. The algorithm is emulated on computer and tested on-line with our ACC vehicle.

• 교육시설 논문지
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• 제27권2호
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• pp.3-13
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• 2020

The purpose of this study was to analyze the factors negatively affecting college life, to investigate the perception gap between housing types, and to generate preliminary data for increasing residential satisfaction of students who live in temporary housing(e.g., dormitory or one-room). The utilized research methods included a questionnaire survey and an in-depth interview. The college students, especially from other regions, experienced more financial difficulties than others. They managed their tuition and living expense/allowance by parents supports and other sources(e.g., scholarship, arbeit, work in college, loan etc.). The reasons to choose dormitory, as temporary housing, were short distance to college and low costs. In case of one room, independent life was main reason to choose. Gender differences affected to the decision, moving away from present temporary housing. For example, male students preferred an independent life and a short commuting distance, while female students preferred an independent life and a safe life. Thus, considering the origin and gender differences of residents, dormitory planning needed to develop plans allowing independent life and to choose appropriate site for the purpose. In case of planning one room apartment, concerns for safety and landscape were more important than other factors.

• Archives of Plastic Surgery
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• 제49권4호
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• pp.473-478
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• 2022

Background We investigate the effect of involutional blepharoptosis (IB) surgery based on dry eye symptoms by analysis using objective and subjective measures. Methods We recorded various parameters from patients that underwent levator advancement surgery for IB, totaling 125 eyes (total 65 patients, 5 unilateral, 60 bilateral). Subjective assessment comprised a questionnaire on dry eye-related quality of life score (DEQS), a summary score calculated from DEQS, and six-grade evaluation, the patient's own measure of eye comfort. Objective assessment comprised marginal-reflex distance-1 (MRD-1), measurement of tear film breakup time, and superficial keratopathy (SPK) existence by slit lamp microscope. Results Subjective assessments showed that IB patients had improvement of dry eye symptoms and eye comfort when surgery increased MRD-1. On the other hand, objective assessments showed that the presence of SPK is suspected when the postoperative MRD-1 level is 3 mm or higher. Conclusion IB surgery must not only increase MRD-1 value, but also to perform maintenance of the appropriate ocular surface condition. From our parameters, we suggest postoperative MRD-1 value should be maintained at < 3 mm to safe and effective of IB surgery.

• 화약ㆍ발파
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• 제28권2호
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• pp.17-27
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• 2010

현대사회의 발전과 더불어 기술적인 진보는 물론이고 보안물건의 의미, 형태 및 종류가 다양해지고 있지만, 총포도검화약류등단속법은 1961년에 제정된 이래 2010년 지금까지 현실적으로 개정이 되지 않아 화약류사용 및 저장에서 행정상의 문제점이 제기되고 있다. 따라서 본 연구에서는 정부기관에 질의된 민원인들의 질의 및 회시에 대한 관련사례를 조사하고 이들 보안물건 등급에 대한 영향을 분석하기 위해서 음압해석 시뮬레이션 프로그램인 ENPro 3.1을 이용하여 화약류저장소 폭발시의 폭풍압에 대한 시뮬레이션을 하고, 전달된 폭풍압의 피해영향 규모를 비교하여 공학적인 방법으로 현행 보안물건의 등급에 따른 보안거리의 규정에 대한 문제점을 연구하였다. 그 결과 저장소 주변의 지형 및 지물을 고려하지 않은 1종 보안물건의 법률상의 보안거리 440m에서의 폭풍압 크기와 지형지물을 고려한 실제 이격거리 309m에서의 폭풍압 크기를 분석 대비한 결과 각각 138dB(L)과 123dB(L)로 계산되었다. 따라서 지형지물이 있는 경우가 근거리에 보안물건이 존재하더라도 440m의 경우보다 309m 지점에서 지형지물이 존재하면 약 15dB(L)이 작은 수치를 보여 근거리의 보안물건이 더욱 폭풍압의 영향이 적은 것으로 나타났다. 그래서 저장소 주변의 지형지물이 고려되지 않은 보안거리의 적용은 부적합하므로 저장소의 주변환경을 고려한 공학적 분석결과에 의해 보안거리가 적용되어야 할 것으로 사료된다.

• Archives of Plastic Surgery
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• 제35권1호
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• pp.28-35
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• 2008

Purpose: The pedicle of transverse rectus abdominis myocutaneous(TRAM) flap and deep inferior epigastric arterial perforator flap is deep inferior epigastic artery (DIEA) and accurate anatomic knowledge about perforator of DIEA is very important for the elevation of these flap. The authors investigated a detailed vascular network of perforator of DIEA in Koreans. Methods: 24 fresh cadavers were studied. Among them, 15 were examined based on the plain X-ray examination for the distribution and location of perforator of DIEA. And 9 fresh cadavers were examined based on the 3-dimensional computed tomography(CT) study for the distance between ending point of perforator of DIEA and mother artery, the distance between most medial mother artery and midline, the distance between most lateral mother artery and midline, and the running type of perforators of DIEA. Results: Based on the plain X-ray examination, suitable(external diameter$${\geq_-}0.5mm$$) perforators of DIEA are located between the level of umbilicus and 8 cm below it. Based on the 3D-CT study, average distance between the ending point of perforator of DIEA and the mother artery is 30.26 mm on the left, 28.62 mm on the right, respectively. The average distance between most medial mother artery and midline is 17.13 mm on the left, 15.76 mm on the right, respectively. The average distance between most lateral mother artery and midline is 56.31 mm on the left, 50.90 mm on the right, respectively. The main running course of suitable perforators of DIEA is type a, which is a direct musculocutaneous perforator vessel from main vascular axis passing outward to join the subdermal plexus, directly. Conclusion: 3-dimensional computed tomography study as well as plain X-ray examination provided more accurate and detail informations about perforators of DIEA in Koreans. These informations will help us understand the detailed vascular anatomy and operation with ease and safe in the lower abdomen of Koreans.

• 한국측량학회지
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• 제39권6호
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• pp.549-554
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• 2021

정밀한 3차원 도로공간정보는 자율주행을 위한 기본 인프라로 안전한 자율주행을 위한 필수 데이터라 할 수 있다. MMS (Mobile Mapping System)은 도로공간정보 구축을 위한 장비로 활용되고 있으며, 관련 연구가 수행되고 있다. 하지만 MMS를 활용한 성과물의 정확도에 중요한 요인이 되는 기준점 거리가 성과물의 정확도에 미치는 영향을 분석한 연구는 부족한 실정이다. 이에 본 연구에서는 MMS를 이용하여 취득되는 데이터의 기준점 거리별 정확도를 분석하고자 하였다. 연구대상지 도로에 대해 MMS를 이용하여 포인트클라우드 데이터를 구축하였다. 데이터 처리는 MMS 데이터는 기준점과의 거리를 고려하여 4개의 데이터를 구축하였으며, 정확도 평가를 위해 12개의 검사점 성과와 비교하여 정확도를 분석하였다. MMS 데이터의 정확도는 수평방향으로 -0.09m~0.11m, 높이방향으로 0.04m~0.19m의 차이를 나타내었다. 수평방향에 비해 수직방향의 오차가 크게 나타났으며, 기준점과의 거리가 증가함에 따라 정확도가 감소함을 알 수 있었다. 또한 구간의 거리가 길어질수록 기준점과의 거리가 하나의 데이터 셋에서 달라질 수 있기 때문에 추가적인 연구가 필요하며, 향후 여러 개의 기준점을 사용하는 방법에 대한 정확도 평가가 이루어진다면 정밀한 도로공간정보 구축을 위한 효과적인 기준점 활용 방안을 제시할 수 있을 것이다.

• Journal of Acupuncture Research
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• 제33권2호
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• pp.77-87
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• 2016

Objectives : This is a pilot study for a large randomized controlled trial to investigate the efficacy and safety of a newly developed contrast therapy device-- alternating topical heat and cold -- for patients with chronic low back pain. The main objective of this study is to confirm the feasibility of the study design. Methods : The design was a randomized, 2-arm, parallel-group, single-blind, placebo controlled trial. Patients in each group received real or sham contrast therapy in an acupuncture point 10 times over four weeks. The primary outcome measure was pain intensity on a 100-mm visual analogue scale (VAS). The secondary outcomes were back-related dysfunction based on the Oswestry Disability Index (ODI), the Roland-Morris disability questionnaire (RMDQ), and range of motion of lumbar spine based on the modified Schober test (mSchober test), Finger-to-Floor distance (FTF distance), and Finger-to-Thigh distraction (FTT distraction). Results : A total of 30 subjects with chronic low back pain were randomly assigned to a contrast therapy group (n＝15) or a sham group (n＝15). A repeated-measures analysis of variance showed statistically significant group time interaction for VAS, RMDQ, mSchober test and FTF distance (p<0.05). The treatment group showed significant improvement in pain intensity and functional disability as compared to the sham group. Conclusion : Contrast therapy may be an effective and safe treatment for chronic low back pain.

• 한국안전학회지
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• 제26권2호
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• pp.99-106
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• 2011

There is a high potentiality of large traffic accident due to the dense fog when road is developed along the coast or river. The establishment of national level control system against the fog is necessary because the accident due to the creation of fog has a high fatality ratio than other weather conditions. The selection method for the frequent foggy area on highway was suggested to control the fog on the highway effectively because the establishment of the countermeasure against the fog in every range in highway is difficult practically. 44 ranges where the fog control is necessary throughout the year and the 45 ranges where the control is necessary in specific months were selected from the result of application of the weighted value on each visible distance data except the fog with beyond 250 m visible distance which does not affect on the safe driving out of the surveyedjsh fog visible distances. The preferential fog control countermeasure shall be provided to prevent the traffic accident and to reduce the severeness of the accident in case of fog creation for 89 ranges which were selected for frequent foggy area in highway.

• Geomechanics and Engineering
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• 제11권5호
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• pp.607-624
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• 2016

Rockburst is becoming more serious in Chinese coal mine. One of the effective methods to control rockburst is blasting. In the paper, we monitored and analyzed the blasting waves at different blast center distances by the Hilbert-Huang transform (HHT) in a coal mine. Results show that with the increase of blast center distance, the main frequency and amplitude of blasting waves show the decreasing trend. The attenuation of blasting waves is slower in the near blast field (10-75 m), compared with the far blast field (75-230 m). Besides, the frequency superposition phenomenon aggravates in the far field. A majority of the blasting waves energy at different blast center distances is concentrated around the IMF components 1-3. The instantaneous energy peak shows attenuation trend with the blast center distance increase, there are two obvious energy peaks in the near blast field (10-75 m), the energy spectrum appears "fat", and the total energy is greater. By contrast, there is only an energy peak in the far blast field, the energy spectrum is "thin", and the total energy is lesser. The HHT three dimensional spectrum shows that the wave energy accumulates in the time and frequency with the increasing of blast center distance.