• 소음진동
• /
• 제8권5호
• /
• pp.974-980
• /
• 1998

본 논문은 직교이방성 탄성계에서 내부 선형하중에 의한 탄성파의 거동을 고찰하였다. 첫째로, 내부 발진원에 대한 탄성과 거동식을 무한계와 반구계에서의 직교이방성 매체에서 유도하였고, 둘째로 Cargniard-DeHoop을 이용하여 순간선형하중에 대한 무한계와 반구계에서의 탄성과 거동식을 유도하였다. 반구계에서 탄성파에 대한 거동식은 무한계에서 유도한 결과와 반구의 표면에서 분산되는 반사파의 합으로 표현되고, 경계영역에서 경계조건을 만족하였다. 여러 가지 이방성 매체에 대한 수치해석 결과를 제시하였고, 이방성 매체의 특성인 bulk wave의 Lacunae 및 표면파의 영향을 고찰할 수 있었다. 본 논문의 결과는 지진연구, 복합소재 특성 연구, 지능형소재 특성연구 등에 응용될 것이다.

• Interaction and multiscale mechanics
• /
• 제2권1호
• /
• pp.31-44
• /
• 2009

While the classical theory of Griffith is the foundation of modern understanding of brittle fracture, it has a number of significant shortcomings: Griffith theory does not predict crack initiation and path and it suffers from the presence of unphysical stress singularities. In 1998, Francfort and Marigo presented an energy functional minimization method, where the crack (or its absence) as well as its path are part of the problem's solution. The energy functionals act on spaces of functions of bounded variations, where the cracks are related to the discontinuity sets of such functions. The new model presented here uses modified energy functionals to account for molecular interactions in the vicinity of crack tips, resulting in Barenblatt cohesive forces, such that the model becomes free of stress singularities. This is done in a physically consistent way using recently published concepts of Sinclair. Here, for the consistency of the model, it becomes necessary to allow for crack reversibility and to consider local minimizers of the energy functionals. The latter is achieved by introducing different time scales. The model is solved in its global as well as in its local version for a simple one-dimensional example, showing that local minimization is necessary to yield a physically reasonable result.

• 한국디지털건축인테리어학회논문집
• /
• 제9권1호
• /
• pp.49-59
• /
• 2009

This study examined the programs of public library and the spaces for them in Seoul and Gyunggi area. The examination was performed by making field surveys on 12 sample public libraries and posing user questionnaires on 4 libraries out of the sample. The data from the questionnaire survey were processed and analyzed with SPSS 14.0. The results are as follows: First, according to the arrangement of the furniture, the space usages for the programs in public libraries are divided into four classes, one-way exposure: free of furniture: two-way exposure. The one-way exposure has been the most common though the furniture arrangement varies with the characteristics of a program. Second, language or information technology related programs are the most frequently attended programs in public libraries. Lastly, the space usage for the reading education programs has had the highest level of the user satisfaction measurement while the user satisfaction is lower in those for general culture programs and health care programs.

• 한국환경과학회지
• /
• 제25권9호
• /
• pp.1223-1231
• /
• 2016

To create urban landscapes that take human emotion into consideration, the present study verified the psychological effects of artificial waterscape facilities on users, as these facilities significantly impact their psychological comfort. Data was collected using the SD scales and POMS of 60 male and 60 female participants after they watched a video of four waterscape facilities. Participants deemed the video clip of a fountain waterscape to be artificial and linked it with changeable images that increased their vigor. The video clip of waterfall stimulated various impressions (e.g., vital, liked, active, etc.) and changed participant' mood states by increasing their vigor and decreasing fatigue. The video clip of the pond yielded familiar impressions, produced less free images, and decreased tension among participants. Finally, the video clip of the stream stimulated quiet and comfortable images as well as reduced negative feelings of anger, confusion, and depression among participants. Furthermore, males experienced more positive effects than females, regardless of the type of waterscape facility. The study findings indicate that the four different waterscape facilities influenced participants' mood states. Additionally, the psychological effects differed by gender. The data suggest that landscape planners need to carefully consider their choice of waterscape facility when designing green spaces to ensure that the space is psychologically comforting to users.

• 한국환경과학회지
• /
• 제25권12호
• /
• pp.1673-1688
• /
• 2016

Gyeonghuigung palace is an important site as it was the secondary palace in Hanyang from the $17^{th}$ century to the mid-$19^{th}$ century. Its original state was lost because a number of buildings were damaged and the palace area was reduced. The entire palace can be seen only in "Seogwoldoan" a drawing of the western palace. With "Seogwoldoan" to show the complete configuration of Gyeonghuigung palace in detail as the main data and other relevant data used as supplementary sources, the aim of this work was to identify the figurative features around the plantings and the space configuration of the royal garden in Gyeonghuigung palace. The space configuration observed in the royal gardens in Gyeonghuigung palace deviated from the norms and strict systems of royal palaces. The free and uninhibited configuration of the royal garden was allowed in Gyeonghuigung palace because it was built as a secondary palace in a lower hierarchy. Furthermore, a royal garden characterized by unique and unlimited planting was created, with several spaces acting as both royal garden and rear garden as the rear gardens could not be separately configured due to the narrow space of Gyeonghuigung palace.

• 한국조경학회지
• /
• 제36권1호
• /
• pp.12-27
• /
• 2008

The purpose of this plan was to introduce the imaginary environment concept to modem environment design which was drawn by comparison of historic and cultural landscape. An area of $19,056m^2$ in I1-ja mountain water reservoir, located in 94 Dun-Chon-Dong, Gangdong-Gu, Seoul was selected for this planning. The concepts of Barrier-Free Design and Universal Design were introduced in order to accept the demands of various social classes. Based on the results of natural and cultural environment, Animism, Heaven, Earth and Man Theory and Yin-Yang and the Five Elements Theory these concepts were introduced for the philosophical background. Concept planning, topic selection, space planning and axis establishment were conducted during the framework step of the plan. Circulation planning, planting planning, facility and pavement planning, and light planning were conducted during the initial planning step. Lastly, detailed designing was performed for the major spaces. In addition, the imaginary environment concept was applied, ranging from the structural aspect of the space to designing factors of the facility in order to achieve placeness and practicality. In conclusion, this may be the first case design applying the imaginary environment concept to the environmental design with natural environment factors such as animals, plants, terrains and climate, and cultural such as cities, places, time, thoughts and symbols which are all factors to be considered in the existing environment design.

• 한국분말재료학회지
• /
• 제22권6호
• /
• pp.438-442
• /
• 2015

Porous thick film of alumina which is fabricated by freeze tape casting using a camphene-camphor-acrylate vehicle. Alumina slurry is mixed above the melting point of the camphene-camphor solvent. Upon cooling, the camphene-camphor crystallizes from the solution as particle-free dendrites, with the $Al_2O_3$ powder and acrylate liquid in the interdendritic spaces. Subsequently, the acrylate liquid is solidified by photopolymerization to offer mechanical properties for handling. The microstructure of the porous alumina film is characterized for systems with different cooling rate around the melting temperature of camphor-camphene. The structure of the dendritic porosity is compared as a function of ratio of camphene-camphor solvent and acrylate content, and $Al_2O_3$ powder volume fraction in acrylate in terms of the dendrite arm width.

• 한국패류학회지
• /
• 제20권1호
• /
• pp.1-6
• /
• 2004

An anatomical and ultrastructural study on the dart sac and the dart of a Korean snail Nesiohelix samarangae was conducted to understand their morphological characteristics with the help of the light microscope and electron microscopes, TEM and SEM. Nesiolelix samarangae had two darts which are pure white structures 6-8 mm in length, tapering from 0.6-0.8 mm to 0.15-0.3 mm. The dart sac had a long conic lumen subdivided into two by a septal wall, and the darts were centrally embedded in the thick muscular layers of the sac. The darts occupied each of the two luminal spaces one per each. The convexed surfaces of the darts had many crystal buds in the shape of the petals. Otherwise, the convexed surfaces of the darts had numerous crystal buds in the shape of candle or topaz. The luminal surface of the dart sac was covered with a single columnar epithelium. The epithelial cells possessed microvilli on their free surface.

• 한국실내디자인학회논문집
• /
• 제15권6호
• /
• pp.11-18
• /
• 2006

Ceaseless studies and efforts to verify today's Korean nature that has advanced into digital era of 21C are continued. At this point of time, it is required to look back our heritage in diverse points of view free from theoretical and formal studies on our traditional spaces. Phenomenology, which is rising as the important theme in recent modem Western philosophy, suggests interesting analyses from this standpoint. This study is intended to analyze Korea's traditional residents 'Dok Rak Dang' based on Marleau-Ponty's phenomenology, and explore phenomenological spatial principle and new point of view implied in it. Particularly, Marleau-Ponty's phenomenology is the philosophy that shows intersubjective and involved relations between space and human, and intended to accept coincidental incidents occurred by human's action truthfully as they are. With three spatial concepts of direction, depth, and movement in Ponty's phenomenology, and placement nature of the earth that intercombine with human's body who is subject of these three concepts as analyze tool, Korea's traditional residents, 'Dok Rak Dang' has been analyzed. More segmentalized analyses have been deduced, and principle of phenomenology, that perceptions such as direction, depth, movement, etc are working synthetically to be accepted as essence of experiences could also be found in Dok Rak Dang.

• Journal of Power Electronics
• /
• 제11권6호
• /
• pp.837-845
• /
• 2011

This paper proposes phase current reconstruction techniques for two-phase two-leg and two-phase four-leg inverters using a single current sensor. In the proposed methods, one phase current is sampled simultaneously with a particular branch current by using only one current sensor, and then current reconstruction algorithms are applied to extract the information on two phase currents from the sensor output. The sampled current information is periodically updated at the peak and the valley of the triangular carrier waveform in each switching cycle of pulse-width modulation (PWM). The voltage vector spaces where the phase currents can be reconstructed are evaluated. Compared to the existing method using two individual current sensors in two phases, the proposed schemes can save implementation cost since it is possible to remove one current sensor. In addition, the proposed methods are free from gain discrepancy issues between two current sensors. Simulations and experiments show excellent current reconstruction performance of the proposed methods.