• 자원환경지질
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• 제47권6호
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• pp.589-599
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• 2014

본 연구에서는 서해 명사십리 일대의 제 4기 극한재해 퇴적기록 보존지역을 선정하기 위해, 1918년 일제 강점기 지형도, 2000년 수치지형도, 1976년 항공사진 및 2012년 항공사진을 이용하여 작성한 수치표고모델과 지표이용도를 순차 비교 분석하여 연구지역의 퇴적환경 및 지표환경 변화를 고찰하였다. 연구지역의 지형적 특징은 지난 100여 년간 큰 변화가 없었으나 연구지역의 북부와 남부에는 고도의 변화폭이 상대적으로 큰 구릉지가 위치하고 해안에 평행하게 사구가 발달하며 연구지역 남부 사구의 후면으로 내륙에 평탄한 저지대가 위치한다. 연구지역 유수 및 퇴적물의 이동 방향을 분석한 결과 사구에서 내륙으로 이동하는 흐름과 내륙의 높은 지대에서 해안으로 이동하는 흐름이 연구 지역 중부를 가로지르는 하천을 향하여 이동하며 중남부 용정리와 남부 자룡리의 평탄한 저지대에 각각 $0.2km^2$의 넓이를 가지는 저수지역을 형성할 수 있다. 또한 연구지역 해수면 변화기록을 보존하는 지역을 찾기 위하여 해수면을 상승시킨 결과 해수면이 3 m 상승했을 때 침수되는 지역은 1918년 $3.4km^2$, 2000년 $3.64km^2$으로 저수지역이 형성되는 위치와 중첩되며 남부의 평탄한 저지대가 해수범람 퇴적층의 형성이나 퇴적물의 집적에 용이한 환경임을 지시한다. 100여 년간 인간의 활동으로 인한 지표 환경 변화가 제한적이었던 지역은 약 $3.51km^2$의 면적으로 연구지역 중부에서 남부에 분포하며 1918년에는 점토 퇴적지, 논으로 활용되었고 2012년에 이르러서는 모두 논으로 이용되고 있다. 연구지역의 퇴적환경과 지표이용변화를 중첩 분석한 결과, 제4기 퇴적기록을 보존하고 있을 가능성이 가장 높은 지역은 연구지역 중부에 약 $0.15km^2$, 남부에 $0.09km^2$의 면적으로 존재하며 이 지역을 중심으로 과거 이상기후 퇴적기록을 연구하는 것이 효과적일 것으로 기대된다.

• Smart Structures and Systems
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• 제22권3호
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• pp.341-358
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• 2018

This present study investigates Love-type wave propagation in composite structure consists of a loosely bonded functionally graded piezoelectric material (FGPM) stratum lying over a functionally graded initially-stressed fibre-reinforced material (FGIFM) substrate. The closed-form expressions of the dispersion relation have been obtained analytically for both the cases of electrically open and electrically short conditions. Some special cases of the problem have also been studied and the obtained results are found in well-agreement with the classical Love wave equation. The emphatic influence of wave number, bonding parameter associated with bonding of stratum with substrate of the composite structure, piezoelectric coefficient as well as dielectric constant of the piezoelectric stratum, horizontal initial stresses, and functional gradedness of the composite structure on the phase velocity of Love-type wave has been reported and illustrated through numerical computation along with graphical demonstration in both the cases of electrically open and electrically short condition for the reinforced and reinforced-free composite structure. Comparative study has been carried out to analyze the distinct cases associated with functional gradedness of the composite structure and also various cases which reveals the influence of piezoelectricity, reinforcement and horizontal initial stress acting in the composite structure, and bonding of the stratum and substrate of the composite structure in context of the present problem which serves as one of the major highlights of the study.

• Nuclear Engineering and Technology
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• 제7권4호
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• pp.267-275
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• 1975

U-233에 관한 저에너지에 있어서의 분리가 가능한 공명구조를 다 준위 이론을 고려한 아들라-아들라 이론에 의하여 조사하였다. 아들라-아들라의 유효 공명 매개변수를 이용하여 60eV 이하의 에너지 영덕에 있어서의 U-233의 공명 흡수 및 핵분열 단면적을 계산하였다. 또한 상기 단면을 잘 표시하여 줄 수 있도록 정하여진 아들라-아들라 매개변수를 이용하여 U-233에 관한 무한 희석 공명적분을 구하였으며, 이는 여기서 고려한 대부분의 공명 에너지 영역에서 실험과 잘 일치하였다. 또한 원자고 계산에는 유용하나 다 준위 이론을 적응할 수는 없는 현존의 전자계산 코드들을 활용하기 위하여 아들라-아들자의 다 준위 이론에 따른 매개변수를 단일 준위 이론에 의한 가매개변수로 변환하여 이 결과를 표로 표시하였다.

• 대한조선학회지
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• 제2권1호
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• pp.9-14
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• 1965

Ship designers make every efforts to get faster ships in accordance with the development of the Naval Architecture. But for the speed lying over factor length ratio 2.5-3.0, we could put a powerful engine into the conventional round bottom displacement type vessels, but it is very difficult in view point of economy, weight and volume. The principal cause of these speed obstacles is the wave making resistance and researchers are trying to decrease this resistance. One of the resolving ways, planing hulls were applied to small high boats. Planing hull's advantage is not restricted to speed, but the workmanship of the planing hull is easier than those of displacement type vessels of round bottom. Planing hull, therefore, are widely applicable to the intermediate speed boats, which don't have enough high speed to take planing advantage, as well as high speed boats. We will discuss related phenomena of the planing hull in details and this paper we particularly interested in the interjection point(speed length ratio 3.0-3.5 by Mr. D. De Groots) between semi-planing and full planing hulls on the resistance characteristic curve. The paper by Prof. Keuck Chun Kim, "Some Characteristics of Straight Framed V-bottom Hull Forms", Journal of the society of Naval Architects of Korea, Vol.1, No.1, Dec.5, 1964, is referred to the V-bottom hull forms belonging to low speed region and determines practical applicable limit of the speed length ratio combined with construction costs, under which are still used by large commercial vessels. This is the interesting contrast between his and authors. We will further discuss the speed length ratio which is considered as a beginning point to planing effect. For this analysis, we choose 3 model ships: Model (1) and (2) have the same principal dimensions, model 3 varied dimension. Model (1) is full-planing hull, (2) is semi-planing hull and (3) is complete planing hull. They are aimed to collect proper design data for purposed ships.

• 디자인학연구
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• 제12권4호
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• pp.119-128
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• 1999

제품계획에서 제품기획탐색은 세부적인 제품컨셉에 우선하여 제품으로서의 기능성을 분석하는 것으로, 제품환경변화의 분석에 따라 제품의 기회를 발견하여 생산자의 모든 자원과 비교함으로서 새로운 시장을 파악하는 것이다. 따라서 제품기회탐색에는 시장이나 제품에 대한 다양한 데이터와 이를 바탕으로 한 정확한 분석과 직관련이 요구된다. 특히 시장에서 제품을 둘러싼 제반환경의 급격한 변화에 의해 보다 적절하고 다양한 제품정보의 획득과 활용의 중요성이 부각되고 있다. 이러한 상황을 배경으로 할 때 가장 시급하고도 중요한 것은 필요한 제품정보의 유형을 밝히고, 이에 따라 데이터베이스를 구축하는 일이며, 단순히 데이터만을 모아놓는 것이 아니라 문맥정보로의 변환을 위해 체계적인 시스템화가 이루어져야 한다. 이에 본 연구에서는 제품속성을 기준으로 제품디자인 데이터 베이스의 개념적 구조를 밝혔으며 이에 따라 프로토타입을 작성하였다. 또 개발된 프로토타입을 이용하여 데이터를 탐색하고 분석하여 구체적인 제품기회를 얻기 위해 제품경향을 파악하는 일련의 과정을 소형카메라를 사례로 하여 제시하였다.

• 한국학교보건학회지
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• 제24권1호
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• pp.99-109
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• 2011

Purpose: The purpose of this study was to investigate factors influencing dysmenorrhea in middle school girls and to analyze the differences in dysmenorrhea according to personal factors of the subjects. Methods: This study was conducted from March 22 to April 2, 2010. The subjects of the study were 572 girls who attended three middle schools in Seoul and experienced dysmenorrheal. All were surveyed using the same questionnaire. Data were analyzed by the SPSS/WIN 12.0 program and included descriptive statistics, ANOVA and multiple regression analysis. Results: 1) The mean age of the subjects was 13.53 years, and the mean age of first menstruation (menarche) was 11.94 years. The number of days between the onset of menstrual cycles was 30.01 days. Most of the respondents had irregular menstrual cycles and menstrual periods lasting 3 to 7 days long. 2) Chief menstrual pains were lower abdominal and back pain. Subjects reported experiencing severe lower abdominal and/or back pain, most commonly on the second day of menstruation. The average score of menstrual discomfort was over 60 points (63%). The average score per 6 points of dysmenorrhea was as follows: fatigue (3.48), sensitivity (3.27), disability of movement (3.27), napping or lying down (2.98), mood swings (2.95), interference with studies (2.87). 3) Individual subject characteristics influencing the onset of dysmenorrhea were as follows: high stress levels, being in poor health, having an irregular diet, being younger and having longer menstrual periods than most other subjects. Conclusion: During puberty, girls with earlier menarche complained of physical and emotional discomfort, and irregular menstrual periods. Therefore, we need to explain overall menstrual characteristics and individual differences in the occurrence of dysmenorrhea, in health education programs.

• PNF and Movement
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• 제13권2호
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• pp.103-109
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• 2015

Purpose: Abdominal breathing exercises are recommended to activate the breathing muscles and the pelvic floor muscles, as well as to increase postural alignment during exhalation. The purpose of this study was to clarify the effect of improving abdominal muscle strength on menstrual pain in women in their twenties using abdominal breathing exercises. Method: In this study, 32 female university students were included as the subjects. The subjects were divided into two groups based on the area of menstrual pain: lumbar pain (n=16) and lower abdomen pain (n=16). The abdominal breathing positions were divided into two positions, which included a hook lying position and hip and knee flexions at $90^{\circ}$ in the supine position. Exercises were used to strengthen the abdominal muscles during exhalation. Four sets of the exercises were completed three times a week over the course of eight weeks. The degree of pain was measured using the Numeric Rating Scale (NRS). Muscle thickness was measured using an ultrasound. Result: The thickness of the transverse abdominis (TrA) and internal oblique (IO) increased in the lower abdomen pain group. However, thickness of the external oblique (EO) did not increased following abdominal breathing. No significant difference in posture was identified in the lower abdomen group. TrA thickness increased significantly in the lumbar pain group. However, thickness did not increase significantly in the lumbar pain group. In addition, the lumbar pain group experienced no significant effects on posture. IO thickness increased following hip and knee flexions at $90^{\circ}$ in the lumbar pain group. Menstrual pain decreased following intervention in both groups. There was no significant difference in the degree of pain reduction between both groups. Conclusion: As examples of alternative medicine, abdominal breathing exercises may be effective in decreasing menstrual pain.

• 한국수자원학회논문집
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• 제52권3호
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• pp.173-185
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• 2019

한반도는 지형학적 요건으로 인하여 태풍과 관련된 재난이 매년 발생하여 막대한 피해를 유발하고 있다. 태풍 내습시 폭풍해일과 집중호우가 동시에 발생한다면 해안지역의 침수피해는 더욱 증가할 것으로 사료된다. 이러한 관점에서 태풍과 폭풍해일의 상호의존성을 정량적으로 규명하는 것은 해안지역의 재해분석에 필수적이다. 본 연구에서는 Bayesian 기법을 기반으로 절점기준을 초과하는 임계값의 초과확률을 산정하기 위하여 Poisson 분포와 Generalized-Pareto 분포를 이용한 Poisson-GP 폭풍해일 빈도해석 기법을 개발하였다. 본 연구를 통하여 개발된 Poisson-GP 폭풍해일 빈도해석 기법은 설계해수면의 불확실성을 정량적으로 제시하였으며 해안지역의 폭풍해일 관련 방재기술 향상에 기여할 것으로 판단된다.

• Journal of Animal Science and Technology
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• 제64권6호
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• pp.1237-1244
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• 2022

Horse breeders suffer massive economic losses due to dystocia, abortion, and stillbirths. In Thoroughbred mares, breeders often miss the foaling process because approximately 86% of the foaling events occur from 19:00 to 7:00; consequently, breeders cannot assist mares experiencing dystocia. To solve this problem, various foaling alarm systems have been developed. However, there is a need to develop a new system to overcome the shortcomings of the existing devices and improve their accuracy. To this end, the present study aimed to (1) develop a novel foaling alarm system and (2) compare its accuracy with that of the existing Foalert^TM system. Specifically, eighteen Thoroughbred mares (11.9 ± 4.0 years old) were included. An accelerometer was used to analyze specific foaling behaviors. Behavioral data were transmitted to a data server every second. Depending on the acceleration value, behaviors were automatically classified by the server as categorized behaviors 1 (behaviors without change in body rotation), 2 (behaviors with sudden change in body rotation, such as rolling over), and 3 (behaviors with long-term change in body rotation, such as lying down laterally). The system was designed to alarm when the duration of categorized behaviors 2 and 3 was 12.9% and that of categorized behavior 3 was 1% during 10 min. The system measured the duration of each categorized behavior every 10 min and transmitted an alarm to the breeders when foaling was detected. To confirm its accuracy, the foaling detection time of the novel system was compared with that of Foalert^TM. The novel foaling alarm system and Foalert^TM alarmed foaling onset respectively 32.6 ± 17.9 and 8.6 ± 1.0 min prior to foal discharge, and the foaling detection rate of both systems was 94.4%. Therefore, the novel foaling alarm system equipped with an accelerometer can precisely detect and alert foaling onset.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2000년도 춘계학술발표회 초록집
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• pp.1-1
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• 2000

The results of the modification of metal materials treated by high temperature pulst:d plasma fluxes (HTlPPF) with a specific power of incident flux changing in the $(3...100)10^5{]\;}W/cm^2$ range and a pulse duration lying from 15 to $50{\;}\mu\textrm{s}$ have been presented. The results of HTPPF action were studied on the stainless steels of 18Cr-l0Ni, 16Cr- 15Ni, 13Cr-2Mo types; on the structural carbon steels of (13...35)Cr, St. 3, St. 20, St. 45 types; on the tool steels of U8, 65G, ShHI5 types, and others; on nickel and high nickel alloy of 20Cr-45Ni type; on zirconium- and vanadium-base alloys and other materials. The microstructure and properties (mechanical, tribological, erosion, and other properties) of modified materials and surface alloying of metals exposed to HTPPF action have been investigated. It was found that the modification of materials by HTPPF resulted in a simultaneous increase of several properties of the treated articles: microhardness of the surface and layers of 40...60 $\mu\textrm{m}$ in depth, tribological characteristics (friction coefficient, wear resistance), mechanical properties ({\sigma_y}, {\;}{\sigma_{0.2}}.{\;}{\sigma_r}) on retention of the initial plasticity ($\delta$), corrosion resistance, radistanation erosion under ion irradiation, and others. The determining factor of the changes observed is the structural-phase modification of the near-surface layers, in particular, the formation of the fine cellular structure in the near-surface layers at a depth of $20{\;}{\mu\textrm{m}}$ with dimension of cells changing in the range from 0.1 to $1., 5{\;}\mu\textrm{m}$, depending on the kind of material, its preliminary treatment, and the parameters of plasma fluxes. The remits obtained have shown the possibility of purposeful surface alloying of metals exposed to HTPPF action over a depth up to 20...45 $\mu\textrm{m}$ and the concentration of alloying element (Ni, Cr, V) up to 20 wt.%. Possible industrial brunches for using the treatment have been also considered, as well as some results on modifying the serial industrial articles by HTPPF.