• Title/Summary/Keyword: concept of angle

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Simulation of Solid Particle Sedimentation by Using Moving Particle Semi-implicit Method (고체 입자형 MPS법을 이용한 토사물 퇴적 시뮬레이션)

  • Kim, Kyung Sung;Yu, Sunjin;Ahn, Il-Hyuk
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.24 no.1
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    • pp.119-125
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    • 2018
  • The particle based computational fluid dynamics (CFD) method, which follow Lagrangian approach for fluid dynamics, fluid particle behavior by tracking all particle calculation physical quantities of each particle. According to basic concept of particle based CFD method, it is difficult to satisfy continuum theory and measure influences from neighboring particle. Article number density and weight function were used to solve aforementioned issue. Difficulties continuum mean simulate non-continuum particles such as solid including granular and sand. In this regard, the particle based CFD method modified solid particle problems by replacing viscous and surface tension forces friction and drag forces. In this paper, particle interaction model for solid particle friction model implemented to simulate solid particle problems. The broken dam problem, which is common to verify particle based CFD method, used fluid or solid particles. The angle of repose was observed in the simulation results the solid particle not fluid particle.

The Characteristics analysis of a Flux-lock Type Fault Current Limiter according to the Winding Directions for Power Grid (전력계통 적용을 위한 결선방향에 따른 자속구속형 한류기의 특성 분석)

  • Lee, Mi-Yong;Park, Jeong-Min
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.11
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    • pp.5879-5884
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    • 2013
  • With the rapid industrialization and economical development, the electricity demands of the industrial facilities and densely populated large cities are continuing to increase in Korea. The increase in the power consumption requires the extension of power facilities, but it is difficult to secure spaces for equipment installation in the limited space of urban areas. In addition, the 154 kV or 345 kV transmission systems in Korea has a short transmission distance, and are connected to one another in network structures that ensure the high reliability and stability of power supply. This structure reduces the impedance during the fault in power system, and increases the magnitude of in the short circuit fault current. The superconducting fault current limiter (SFCL) was devised to effectively address these existing problems. The SFCL is a new-concept eco-friendly protective device that ensures fast operation and recovery time for the fault current and does not need additional fault detection devices. Therefore, many studies are being conducted around the world. In this paper, based on the wiring method the initial fault current characteristics, current limiting characteristics, according to the incident angle and the change in inductance current limiting characteristics were analyzed in a multifaceted methods.

Collision Strength Assessment for Double Hull Type Product Carrier Using Finite Element Analysis (이중 선체 화학 운반선의 충돌 강도 평가)

  • Paik, Jeom-Kee;Lee, Jae-Myung;Lee, Kyung-Ern;Won, Suk-Hee;Kim, Chelo-Hong;Ko, Jae-Yong
    • Journal of Navigation and Port Research
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    • v.28 no.6
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    • pp.481-489
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    • 2004
  • Ship collisions and grounding continue to occur regardless of continuous efforts to prevent such accidents. With the increasing demand for safety at sea and for protection of the environment, it is of crucial importance to be able to reduce the probability of accidents, assess their consequences and ultimately minimize or prevent potential damages to the ships and the marine environment. Numerical simulations for actual collision problem are conducted with a special attention with respect to finite element size, fracture criteria and material properties, which require a careful consideration to improve the accuracy. A parametric analysis varying colliding speed, angle, design loading condition is conducted using nonlinear finite element analysis method for 46,00 dwt Product/chemical carrier. The relationship between the absorbed energy and indentation are derived quantitatively using the insights observed from this study, and a novel design concept for assessing the anti-collision performance are proposed.

Study of the Incremental Dynamic Inversion Control to Prevent the Over-G in the Transonic Flight Region (천음속 비행영역에서 하중제한 초과 방지를 위한 증분형 동적 모델역변환 제어 연구)

  • Jin, Tae-beom;Kim, Chong-sup;Koh, Gi-Oak;Kim, Byoung-Soo
    • Journal of Aerospace System Engineering
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    • v.15 no.5
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    • pp.33-42
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    • 2021
  • Modern aircraft fighters improve the maneuverability and performance with the RSS (Relaxed Static Stability) concept and therefore these aircrafts are susceptible to abrupt pitch-up in the transonic and moderate Angle-of-Attack (AoA) flight region where the shock wave is formed and the mean aerodynamic center is moved forward during deceleration. Also, the modeling of the aircraft flying in this flight region is very difficult due to complex flow filed and unpredictable dynamic characteristics and the model-based control design technique does not fully cover this problem. In this paper, we analyzed the performance of the TPMC (Transonic Pitching Moment Compensation) control based on the model-based IDI (Incremental Dynamic Inversion) and the Hybrid IDI based on the model and sensor based IDI during the SDT (Slow Down Turn) in transonic region. As the result, the Hybrid IDI had quicker response and the same maximum g suppression performance and provided the predictable flying qualities compared to the TPMC control. The Hybrid IDI improved the performance of the Over-G protection controller in the transonic and moderate AoA region

The Development of Self-Directed CAI Using Web - The main theme is the figure part of mathematics - (웹을 이용한 자기 주도적 CAI 개발 - 수학과 도형영역 중심 -)

  • Kang, Seak;Ko, Byung-Oh
    • Journal of The Korean Association of Information Education
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    • v.5 no.1
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    • pp.33-45
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    • 2001
  • In order to adapt ourselves to the Informationalization Society of twenty-first century, it is required to have ability to find quickly the necessary information and solve the problem of our own. In the field of school, it should be educated to develop learner's ability that can cope with the Informationalization Society. When a learner can study in such direction, he or she will be able to plan the learning of his own as the subject of education, and develop his ability to solve the problem by collecting and examining various information. It is self-leading learning that can make education like this possible. Through computer, especially Web site, self-directed learning can develop can develop the individuality and creativity of learners. They can collect and utilize autonomously information and knowledge. To do such an education, the program that can work out self-directed learning is needed. Therefore the program I want to develop is to reconstruct the 'figure' part of mathematics in elementary school into five steps by utilizing Web site. In the first step is to learn the concept of various shape. This step enable learners to know what figure is and how it can be utilized in our real life. The second step of dot, line and angle makes it possible that learners can consolidate the foundation of the study about figure and recognize the relation between angle and figure. In the third step of plane figure, we can study how to calculate the relation of plane figures and the area of figure with various shapes by cutting and adding them. The fourth step is about congruence and symmetry. Learners can learn to know the figure in congruence, reduction and enlargement and how it is used in our real life. In the fifth step of solid figure, we can learn the relation among the plane figure, solid figure, the body of revolution, corn and pyramid etc. controling the speed of learning on the basis of his ability. In the process of the program, it is also possible to develop learner's ability of self-leading learning by solving the problem by himself. Because this program is progressed on the Web site, it is possible to learn anytime and anywhere. In addition to it, a learner can learn beyond the grade as well as do the perfect learning by controling the pace of learning on the basis of his ability. In the process of the program, it is also possible to develop learner's ability of self-leading learning by solving the problem by himself.

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Performance Evaluation of WWTP Based on Reliability Concept (신뢰성에 기초한 하수처리장 운전효율 평가)

  • Lee, Doo-Jin;Sun, Sang-Woon
    • Journal of Korean Society of Environmental Engineers
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    • v.29 no.3
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    • pp.348-356
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    • 2007
  • Statistical and probabilistic method was used in the analysis of data, which is the most effective one in describing the various natures, and the methodology relating the results with the design was developed. Influents and effluents of three treatment plants were analyzed and the focus was made on BOD, COD, SS, IN, TP The fluctuations of influent such as BOD, COD, SS were extremely large and their standard deviations(st.dev) were more than 10 mg/L. but those of TN, TP were small; the st.dev was 6.6 mg/L for TN, 0.6 mg/L for TP, respectively. But, effluent concentration showed consistent pattern regardless of the influent fluctuations, the st.dev was ranged between 0.28 and 4.48 mg/L. Effluent distributional characteristics were as follows; BOD, COD were distributed normally, but SS, TN, and TP, log-normally; unsymmetric and skewed to the right. The coefficient of reliability(COR) based on the results of statistics of data was introduced to evaluate the process performance an4 to reflect the process performance to the process design. The coefficient of reliability relates the design value(the goal) with the standards and it can be used in operating treatment facilities under a certain reliability level and/or in evaluating the reliability of the treatment facilities on operation. Each treated water quality of effluent showed the half of water quality standards in the level of 50% percentile and all treatment plant was achieved 100% probability of water quality standards. It was concluded that the variability of the process performance should be reflected to the design procedure and the standards through the analysis based on the statistics and the probability.

A study of convergence correlation between freeform architecture classification of museum and exhibition space -Focus on the Netherlands, Germany and Singapore- (박물관의 비정형건축형태분류와 전시공간과의 융합상관성 고찰 - 네덜란드, 독일, 싱가포르를 중심으로 -)

  • Oh, Sun Ae
    • Korea Science and Art Forum
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    • v.37 no.4
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    • pp.205-216
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    • 2019
  • Today, there have been more museums with architectural freeform structure. From an academic perspective, that caused a change in the paradigm of the genealogy of architectural forms. Accordingly, it has been required to find whether the freeform architecture influences an exhibition space. Therefore, in order to analyze the correlation between freeform architecture and exhibition space, this study looks into the tendency of actual freeform architecture through case analysis after 2000. An exhibition space of museum serves as a socially, culturally, and locally symbolic icon and has the function of delivering information to viewers through the aesthetic presentation of articles on exhibition. This study is meaningful in the point that it drew the conclusion of the correlation between freeform architecture and exhibition space in order to infer that a freeform exhibition space is more effective at viewers' spatial experience. The method and results of this study are presented as follows: Firstly, literature survey on the concept of the freerform architecture of museum and the classification of architectural forms was conducted and previous studies were analyzed in order to establish criteria. Secondly, a case study was conducted through visits to Singapore, Germany, and the Netherlands in order to look into the current state and characteristics of freeform architecture and exhibition space. In this case, Karel Vollers' architectural freeform criteria were used for analysis. Thirdly, to prove the correlation between freeform architecture and exhibition space, each case was cross-checked on the basis of Karel Vollers' architectural freeform criteria and freeform exhibition classification, and then results were drawn. The study results are presented as follows: Firstly, EX(angle, ortho) of freeform architecture had a significant correlation with the diagonal form of exhibition space. That was proved 92.3% accurately more in the Netherlands and Germany than in Singapore. However, the curve form of exhibition space had a unclear correlation. In Singapore case, the curve form correlation was made through RO, FR, and TW. Secondly, freeform architecture had complex-typed combination with the diagonal and curve forms of exhibition space. In particular, N-02 and G-02 had a combination form, basically EX, and partially various forms so as to induce the complexity of free form. As such, architectural freeform makes it possible to achieve infinite transformation in various combinations. For responses, combinational approaches are required in multilateral ways. Based on this study, it will be planned to analyze the correlation between freeform architecture of museum and exhibition presentation.

Symmetric-Invariant Boundary Image Matching Based on Time-Series Data (시계열 데이터 기반의 대칭-불변 윤곽선 이미지 매칭)

  • Lee, Sanghun;Bang, Junsang;Moon, Seongwoo;Moon, Yang-Sae
    • KIPS Transactions on Software and Data Engineering
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    • v.4 no.10
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    • pp.431-438
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    • 2015
  • In this paper we address the symmetric-invariant problem in boundary image matching. Supporting symmetric transformation is an important factor in boundary image matching to get more intuitive and more accurate matching results. However, the previous boundary image matching handled rotation transformation only without considering symmetric transformation. In this paper, we propose symmetric-invariant boundary image matching which supports the symmetric transformation as well as the rotation transformation. For this, we define the concept of image symmetry and formally prove that rotation-invariant matching of using a symmetric image always returns the same result for every symmetric angle. For efficient symmetric transformation, we also present how to efficiently extract the symmetric time-series from an image boundary. Finally, we formally prove that our symmetric-invariant matching produces the same result for two approaches: one is using the time-series extracted from the symmetric image; another is using the time-series directly obtained from the original image time-series by symmetric transformation. Experimental results show that the proposed symmetric-invariant boundary image matching obtains more accurate and intuitive results than the previous rotation-invariant boundary image matching. These results mean that our symmetric-invariant solution is an excellent approach that solves the image symmetry problem in time-series domain.

A Study on Soviet Constructive Fashion in 1920s (1920년대 소비에트 구성주의 패션에 관한 연구)

  • 조윤경;금기숙
    • Journal of the Korean Society of Costume
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    • v.36
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    • pp.183-203
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    • 1998
  • The wave of Avant-garde swept away all in the unique social background so called 'October Revolution' and the early 1900 Russian society which was able to absorb and accept anything. The Russian avant-garde has been affected by the Cubism and the Futurism those had peculiarly appeared in the early twentieth century, spreaded out to three spheres: the Suprematism, the Rayonism and the Constructivism. The Russian Constructivism has appeared in this background, concretely and ideally ex-pressed the ideology of the revolution into the artistic form and made an huge influence to the whole Russian society. The Constructivist like Tatlin, naum Gabo, Pevaner, Rodchenko, Stepanova, Popova and Exter gave great effect on the Soviet Constructive fashion design in 1920's after the Revolution. The Soviet costume in 1920s hold in common the characteristicss of the Constructive graphic as it is, geometrical and abstractive form, energetic and motility. In fashion design, these graphic qualities have been showed as the application of geometrical form and architectural image, physical distortion and transformation. And in textile design, the simple, dynamical presentation has been appeared. We can classify the Soviet costume at this time into three occasions. The first term is from late 1910 th mid 1920, and it is altered from folk costume design to modern one. With Lamanova as the first on the list, using the folk mitif, the Constructive expression of simple form has been gradually revealed in design. Designers like Makarova, Pribylskaia and Mukhina produced the plane, simple chemise style with the decoration of the Russian traditional motif. From early to late 1920 is the second term, and it is at the pick of the most active processing of the Constructive design. Not only at the costume in daily life but also at the theatrical costume and textile, the con-structive design has been represented all avail-able fields. Many Constructivists including Stepanova, Popova, Exter and Rodchenko took part in the textile design and costume design so as to evlvo their aesthetic concept. The third term is from late 1920 to early 1930. The socialistic realism has dominated over the whole culture and art, the revolutionary dynamic motif has been presented also in textile design. The formative features of Soviet Constructive fashion design are; silhouette, from, motif, color and fabric. The first, the silhouette : a straight rectangular silhouetted has been expressed through the whole period and a volumed one with distorted human body shape has introduced in the theatrical costume design. The second, the form: many lengthened rectangular forms have been made at beginnings, but to the middle period, geometrical, architectural forms have been more showed and there are energy and movement in design. At the last period, only a partial feature-division has been seen. The third, the motif; no pattern or ethnic motif has been partly used at beginnings, a figure like circle, tri-angle has gradually appeared in textile design. At latter period, a real-existent motif like an airplane has been represented with graphing and simplicity. The fourth, the color ; because of insufficient dyeing, neutral color like black or grey color has been mainly covered, but after middle term, a primary color or pastel tone has been seen, contrast of the fabric; without much development of textile industry after the Revolution, thick and durable fabrics have been the main stream, but as time had going to the last period, fabrics such as linen, cotton, velvet and silk have been varously choesn. At the theatrical costume, new materials like plastics and metals that were able to accentuate the form. The pursuit of popularity, simplicity and functionalism that the basic concept of Constructive fashion is one of the "beauty" which has been searching in modern fashion. And now we can appreciate how innovative and epochal this Soviet Constructive fashion movement was.ement was.

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A Contemplation on Measures to Advance Logistics Centers (물류센터 선진화를 위한 발전 방안에 대한 소고)

  • Sun, Il-Suck;Lee, Won-Dong
    • Journal of Distribution Science
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    • v.9 no.1
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    • pp.17-27
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    • 2011
  • As the world becomes more globalized, business competition becomes fiercer, while consumers' needs for less expensive quality products are on the increase. Business operations make an effort to secure a competitive edge in costs and services, and the logistics industry, that is, the industry operating the storing and transporting of goods, once thought to be an expense, begins to be considered as the third cash cow, a source of new income. Logistics centers are central to storage, loading and unloading of deliveries, packaging operations, and dispensing goods' information. As hubs for various deliveries, they also serve as a core infrastructure to smoothly coordinate manufacturing and selling, using varied information and operation systems. Logistics centers are increasingly on the rise as centers of business supply activities, growing beyond their previous role of primarily storing goods. They are no longer just facilities; they have become logistics strongholds that encompass various features from demand forecast to the regulation of supply, manufacturing, and sales by realizing SCM, taking into account marketability and the operation of service and products. However, despite these changes in logistics operations, some centers have been unable to shed their past roles as warehouses. For the continuous development of logistics centers, various measures would be needed, including a revision of current supporting policies, formulating effective management plans, and establishing systematic standards for founding, managing, and controlling logistics centers. To this end, the research explored previous studies on the use and effectiveness of logistics centers. From a theoretical perspective, an evaluation of the overall introduction, purposes, and transitions in the use of logistics centers found issues to ponder and suggested measures to promote and further advance logistics centers. First, a fact-finding survey to establish demand forecast and standardization is needed. As logistics newspapers predicted that after 2012 supply would exceed demand, causing rents to fall, the business environment for logistics centers has faltered. However, since there is a shortage of fact-finding surveys regarding actual demand for domestic logistic centers, it is hard to predict what the future holds for this industry. Accordingly, the first priority should be to get to the essence of the current market situation by conducting accurate domestic and international fact-finding surveys. Based on those, management and evaluation indicators should be developed to build the foundation for the consistent advancement of logistics centers. Second, many policies for logistics centers should be revised or developed. Above all, a guideline for fair trade between a shipper and a commercial logistics center should be enacted. Since there are no standards for fair trade between them, rampant unfair trades according to market practices have brought chaos to market orders, and now the logistics industry is confronting its own difficulties. Therefore, unfair trade cases that currently plague logistics centers should be gathered by the industry and fair trade guidelines should be established and implemented. In addition, restrictive employment regulations for foreign workers should be eased, and logistics centers should be charged industry rates for the use of electricity. Third, various measures should be taken to improve the management environment. First, we need to find out how to activate value-added logistics. Because the traditional purpose of logistics centers was storage and loading/unloading of goods, their profitability had a limit, and the need arose to find a new angle to create a value added service. Logistic centers have been perceived as support for a company's storage, manufacturing, and sales needs, not as creators of profits. The center's role in the company's economics has been lowering costs. However, as the logistics' management environment spiraled, along with its storage purpose, developing a new feature of profit creation should be a desirable goal, and to achieve that, value added logistics should be promoted. Logistics centers can also be improved through cost estimation. In the meantime, they have achieved some strides in facility development but have still fallen behind in others, particularly in management functioning. Lax management has been rampant because the industry has not developed a concept of cost estimation. The centers have since made an effort toward unification, standardization, and informatization while realizing cost reductions by establishing systems for effective management, but it has been hard to produce profits. Thus, there is an urgent need to estimate costs by determining a basic cost range for each division of work at logistics centers. This undertaking can be the first step to improving the ineffective aspects of how they operate. Ongoing research and constant efforts have been made to improve the level of effectiveness in the manufacturing industry, but studies on resource management in logistics centers are hardly enough. Thus, a plan to calculate the optimal level of resources necessary to operate a logistics center should be developed and implemented in management behavior, for example, by standardizing the hours of operation. If logistics centers, shippers, related trade groups, academic figures, and other experts could launch a committee to work with the government and maintain an ongoing relationship, the constraint and cooperation among members would help lead to coherent development plans for logistics centers. If the government continues its efforts to provide financial support, nurture professional workers, and maintain safety management, we can anticipate the continuous advancement of logistics centers.

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