• Earthquakes and Structures
• /
• v.5 no.1
• /
• pp.83-109
• /
• 2013

A simple damper optimization method is proposed to find optimal damper allocation for shear buildings under both target added damping ratio and interstorey drift ratio (IDR). The damping coefficients of added dampers are considered as design variables. The cost, which is defined as the sum of damping coefficient of added dampers, is minimized under a target added damping ratio and the upper and the lower constraint of the design variables. In the first stage of proposed algorithm, Simulated Annealing, Nelder Mead and Differential Evolution numerical algorithms are used to solve the proposed optimization problem. The candidate optimal design obtained in the first stage is tested in terms of the IDRs using linear time history analyses for a design earthquake in the second stage. If all IDRs are below the allowable level, iteration of the algorithm is stopped; otherwise, the iteration continues increasing the target damping ratio. By this way, a structural response IDR is also taken into consideration using a snap-back test. In this study, the effects of the selection of upper limit for added dampers, the storey mass distribution and the storey stiffness distribution are all investigated in terms of damper distributions, cost function, added damping ratio and IDRs for 6-storey shear building models. The results of the proposed method are compared with two existing methods in the literature. Optimal designs are also compared with uniform designs according to both IDRs and added damping ratios. The numerical results show that the proposed damper optimization method is easy to apply and is efficient to find optimal damper distribution for a target damping ratio and allowable IDR value.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.40 no.7
• /
• pp.261-272
• /
• 2003

An Ethernet PON(Passive Optical Network) is an economical and efficient access network that has received significant research attention in recent years. A MAC(Media Access Control) protocol of PON , the next generation access network, is based on TDMA(Time Division Multiple Access) basically and can classify this protocol into a fixed length slot assignment method suitable for leased line supporting QoS(Quality of Service) and a variable length slot assignment method suitable for LAN/MAN with the best effort. For analyzing the performance of these protocols, we design an Ethernet PON model using OPNET tool. To establish the maximum efficiency of a network, we verify a MAC protocol and determine the optimal number of ONUs(Optical Network Unit) that can be accepted by one OLT(Optical Line Terminal) and propose the suitable buffer size of ONU based on analyzing the end-to-end Ethernet delay, queuing delay, throughput, and utilization.

• Bulletin of the Korean Space Science Society
• /
• 2005.04a
• /
• pp.129-132
• /
• 2005

This paper describes BAUSAT-2 orbital thermal analysis and preliminary design of thermal control subsystem. To design thermal control subsystem of HAUSAT-2, we have considered active & passive thermal control method based on basic theory and themal equilibrium equation. Using this result, suitable thermal control method and material have been selected. We have designed thermal control subsystem based on analysis of HAUSAT-2's thermal environments on sun synchronous orbit with altitude 650km, inclination $98^{\circ}$ and thermal distribution and range expectation of each HAUSAT-2's surface. Thermal analysis consists of system level, box level and board level analysis. We have completed system level and box level analysis. Till now, board level analysis of main heat dissipation board in progress. Thermal control subsystem has designed according to thermal analysis result. This design is to maintain all of the HAUSAT-2 components within the allowable temperature limits. In future, STM

• Journal of Astronomy and Space Sciences
• /
• v.29 no.1
• /
• pp.23-31
• /
• 2012

Thermal analysis and control design are prerequisite essential to design the satellite. In the space environment, it makes satellite survive from extreme hot and cold conditions. In recent years CubeSat mission is developed for many kinds of purpose. Triplet Ionospheric Observatory (TRIO)-CubeSat for Ion, Neutral, Electron, MAgnetic fields (CINEMA) is required to weigh less than 3 kg and operate on minimal 3 W power. In this paper we describe the thermal analysis and control design for TRIO-CINEMA mission. For this thermal analysis, we made a thermal model of the CubeSat with finite element method and NX6.0 TMG software is used to simulate this analysis model. Based on this result, passive thermal control method has been applied to thermal design of CINEMA. In order to get the better conduction between solar panel and chassis, we choose aluminum 6061-T6 for the material property of standoff. We can increase the average temperature of top and bottom solar panels from $-70^{\circ}C$ to $-40^{\circ}C $ and decrease the average temperature of the magnetometer from $+93^{\circ}C$ to $-4^{\circ}C$ using black paint on the surface of the chassis, inside of top & bottom solar panels, and magnetometer.

• Journal of The Korean Digital Architecture Interior Association
• /
• v.10 no.2
• /
• pp.21-30
• /
• 2010

Students in the field of architectural design, form and design of the new learning process, and in the design of a very premiere. Perhaps one way of theoretical training and strict discipline academy will probably already be familiar with. In addition to academic activities rather passive liberal arts students, learning basic academic skills than students, vocational students lag is most. However, these have been popular with young sensibility popular consensus here and he has the potential to move actively. This is very sporadic but does not control the many, it's even the potential fragmentation of consciousness, because they themselves do not know a lot of parts. Therefore, the power embodied in the design process and disclose the outside, it fits in the design field to produce results. And designed to improve learning ability and motivation to want to promote. Accordingly, this research through the following four methods to test the methodology on the basis of the results and try to find solutions to problems. (1) Outside the student's latent ability to express emotion should be. (2) Students' interests are actively utilized in the design classes. (3) Analysis of individual interests and ideas, and how to take advantage of the design process that is induced. (4) The final work should express your own personality into the design. Through this, students' academic motivation and a positive vision of the direction of design is proposed.

• The Transactions of the Korea Information Processing Society
• /
• v.6 no.11
• /
• pp.3020-3033
• /
• 1999

Role-Based Access Control(RBAC) security policy is being widely accepted not only as an access control policy for information security but as both a natural modeling tool for management structure of organizations and flexible permission management framework in various commercial environments. Important functions provided by the current RBAC model are to administrate the information on the components of RBAC model and determine whether user's access request to information is granted or not, and most researches on RBAC are for defining the model itself, describing it in formal method and other important properties such as separation of duty. As the current RBAC model which does not define the definition, design and operation for applications is not suitable for automated information systems that consist of various applications, it is needed that how applications should be designed and then executed based on RBAC security model. In this paper, we describe dynamic properties of session which is taken for a passive entity only activated by users, as a vehicle for building and executing applications in an automated information systems. And, a framework for session-oriented separation of duty property, application design and operation is also presented.

• Journal of the Korea Fashion and Costume Design Association
• /
• v.19 no.2
• /
• pp.117-128
• /
• 2017

This study confirmed the types of shopping information sources during travel abroad, and developed a profile of tourists in terms of demographics, travel, and shopping behavior. Shopping information sources and characteristics of shopping products were identified first. Thereafter, travelers were segmented by their information-seeking behavior. An online survey method was used to get data from Korean vacationers in their 20s-50s, while factor analysis, cluster analysis, ${\chi}^2$ test and ANOVA were applied to analyze data. The results were as follows. First, the shopping information sources of overseas tourists were composed of four factors including sources from travel agents/media, information from travel books and local sources, and word-of-mouth sources. Also, four factors in product types and four product attributes were identified. Second, tourists were clustered into two groups, active and passive shopping information seekers, based on shopping source behavior. Third, two groups differed in terms of demographics, showing an older age and higher income for active shopping source seekers. Active shopping information users tended to join package trips with family members, and they were more satisfied with the trip. With regard to shopping, active shopping source seekers spent more money for shopping and preferred all kinds of shopping goods with an emphasis on travel shopping. In conclusion, shopping information sources seemed to be a meaningful tool for segmenting tourists. Rich, older, family tourists would be an major target market for local retailers.

• Earthquakes and Structures
• /
• v.11 no.4
• /
• pp.701-721
• /
• 2016

Base isolation is a well-established passive strategy for seismic response control of buildings. In this paper, an efficient framework is proposed for reliability-based design optimization (RBDO) of isolated buildings subjected to uncertain earthquakes. The framework uses reduced function evaluations method, as an efficient tool for structural reliability analysis, and an efficient optimization algorithm for optimal structural design. The probability of failure is calculated considering excessive base displacement, superstructure inter-storey drifts, member stress ratios and absolute accelerations of floors of the isolated building as failure events. The behavior of rubber bearing isolators is modeled using nonlinear hysteretic model and the variability of future earthquakes is modeled by applying a probabilistic approach. The effects of pulse component of stochastic near-fault ground motions, fixity-factor of semi-rigid beam-to-column connections, values of isolator parameters, earthquake magnitude and epicentral distance on the performance and safety of semi-rigidly connected base-isolated steel framed buildings are studied. Suitable RBDO examples are solved to illustrate the results of investigations.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.25 no.4
• /
• pp.295-300
• /
• 2016

In the design of passive and active boring bars, the structural dimensions and shape of the vibration control boring bar are modified depending on the diameter and depth of the workpiece, which changes the dynamic behavior. Thus, the natural frequency, effective mass, and stiffness for the main structure of a tube-type boring bar need to be reset for each vibration control case. However, commercial finite element method (FEM) software and experimental modal analysis are mostly used at present despite being too time-consuming. To overcome the weaknesses of the two methods currently used for vibration control, we realized a graphical user interface (GUI) program for the modal analysis of a modified tube-type damping structure. The analysis results with the GUI program were compared to those with commercial FEM software in order to confirm the effectiveness of the former.

• Korean Institute of Interior Design Journal
• /
• no.18
• /
• pp.74-80
• /
• 1999

Chinese medicine hospital enables the users to expect more efficient cure result in the psychological stability and the comfortable indoor environment by supplying the functional and aesthetic cure space with the medical action of good quality Medical activity is to treat the human life. Thus, hospital must be more human-centered-place than other space. Thus study is establishment of space to be able to lead more rational and active participation than the conservative and passive image of the department of diagnosis and treatment for outpatients is desirable. This study is the indoor schedule to suggest the direction about the department of diagnosis and treatment for outpatients of Chinese medicine hospital of native image with more comfortable and positive approach on the basis of above points at issues as the schedule to fulfill the performance of medical function and the emotional and psychological satisfaction of users as the human being-centered-medical institution on the subject of the department of diagnosis and treatment for outpatients in Chinese medicine hospital. And, this researcher progressed as follows by being premised on this 1. Description of Goai, Range and Method of Study and Suggestion of Study Direction 2. Concept introduction as the Basic Approach of Theory which is necessary for Study 3. The Problems were recognized by grasping the present condition in Korea through the questionaines 4. establishment of Concept and direction which are necessary for planning the indoor of the department of Diagnosis and Treatment for Chinese Medicine Hospital 5. Progression of Design Plan attendant upon Concept 6. Analysis of the Conents attendant upon this, and Conclusiov.