• Journal of applied mathematics & informatics
• /
• v.19 no.1_2
• /
• pp.371-384
• /
• 2005

Usual symmetric duality results are proved for Wolfe and Mond-Weir type nondifferentiable nonlinear symmetric dual programs under F-convexity F-concavity and F-pseudoconvexity F-pseudoconcavity assumptions. These duality results are then used to formulate Wolfe and Mond-Weir type nondifferentiable minimax mixed integer dual programs and symmetric duality theorems are established. Moreover, nondifferentiable fractional symmetric dual programs are studied by using the above programs.

• Journal of information and communication convergence engineering
• /
• v.2 no.3
• /
• pp.193-197
• /
• 2004

In this paper, a combination problem of controllers which are the same type of $H_{\infty}$ controllers designed with different weighting functions. This approach can remove the difficulty in the selection of the weighting functions. As a sub-controller, the Youla type of $H_{\infty}$ controller is used. In the $H_{\infty}$ controller, Youla parameterization is used to minimize $H_{\infty}$ norm of mixed sensitivity function by using polynomial approach. Computer simulation results show the robustness improvement and the performance improvement.

• Journal of the Korean Institute of Educational Facilities
• /
• v.23 no.4
• /
• pp.3-10
• /
• 2016

This paper presents the investigation results on the classification of the university campuses. For the classification, we selected the spatial index as the evaluation indicator since the environmental factors and maintenance methods vary from university campus to university campus. For the study, we used eight spatial indices of the 30 national universities. This paper provides the spatial characteristics of different campus types, presents campus classification analysis as a future research approach to campus maintenance, and provides the data for the future study of comparison among universities. The results are as follows. 1) The classification investigation categorized the university campuses into three groups. Type 1 is a large-scale type, located near downtown. Type 2 is a medium-scale type, located at a remote site from downtown. Type 3 is a small-scale type, which is located comparatively near downtown. 2) Type 1 is a large-scale mixed area type, and 13 universities belong to this group. Type 2 is a medium-scale suburban area type, and six universities are in this group. Finally, Type 3 is a small-scale downtown area type, and 11 universities belong to this group.

• Journal of the Korean Physical Society
• /
• v.73 no.9
• /
• pp.1346-1350
• /
• 2018

An electrode-evaporation technology on both the top and bottom sides of the bare vertical-type single chip separated from the traditional substrate by cooling, was developed for III-nitride vertical-type single chip LEDs with thick GaN epilayer. The post-process of the cooling step was followed by sorting the bare vertical-type single chip LEDs into the holes in a pocket-type shadow mask for deposition of the electrodes at the top and bottom sides of bare vertical-type single chip LEDs without the traditional substrate for electrode evaporation technology for vertical-type single chip LEDs. The variation in size of the hole between the designed shadow mask and the deposited electrodes owing to the use of the designed pocket-type shadow mask is investigated. Furthermore, the electrical and the optical properties of bare vertical-type single chip LEDs deposited with two different shapes of n-type electrodes using the pocket-type shadow mask are investigated to explore the possibility of the e-beam evaporation method.

• International Journal of Ocean System Engineering
• /
• v.2 no.4
• /
• pp.250-258
• /
• 2012

The distribution of wave heights is assumed to be a Rayleigh distribution, based on the assumption of a narrow band and Gaussian distribution of wave elevation. The present study was started with doubts about the narrow band assumption. We selected the wave spectra widely used to simulate irregular random waves. The wave spectra used in this study included the Pierson-Moskowitz spectrum, Bretschneider-Mitsuyasu spectrum, and JONSWAP spectrum. The directionality of the waves was considered. The cosine 2-l type directional spreading function and mixed form of the half-cosine 2-s type with Mitsuyasu type directional spreading are considered here to investigate the effects of a directional spreading function on random waves. The simulated wave height distribution is compared with a Rayleigh distribution.

• Journal of the Korean Society for Precision Engineering
• /
• v.14 no.4
• /
• pp.56-63
• /
• 1997

Sealing of lubricant-air mixture in the high performance machining center is one of most the important characteristics to carry out enhanced lubrication. High speed spindle requires non-contact type of sealing mechanism. Evaluating an optimum seal design to minimize leakage is concerned in the aspect of flow control. Effect of geometry and leakage path are evaluated according to variation of sealing geometry. Velocity, pressure, turbulence intensity of profile is calculated to find more efficient geometry and variables. This offers a methodological way of enhancement seal design for high speed spindle. The working fluid is regarded as two phases that are mixed flow of oil phase and air phase. It is more reasonable to simulate an oil jet or oil mist type high speed spindle lubrication. Turbulence and compressible flow model are used to evaluate a flow characteristic. This paper considers a design effect of sealing capability of non- contact type seals for high speed spindle and analyzes leakage characteristics to minimize a leakage 7 on the same sealing area.

• Proceedings of the KIEE Conference
• /
• 2002.07a
• /
• pp.484-486
• /
• 2002

In this paper, installation type is analyzed into a single and mixed burying type on burying situation of domestic underground transmission cables, and problem of underground cable is discussed with investigating the relation between burying type and sheath circulation current. Investigated cable systems are 520 T/L which have 512T/L for 154kV and 8T/L for 345kV. The authors consider that the analysis of sheath circulating current with burying type will contribute for setting reduction methods of sheath circulation current.

• Proceedings of the Korean Institute of Interior Design Conference
• /
• 2001.05a
• /
• pp.29-34
• /
• 2001

The purpose of this study is to provide a practical planning guide for the actual conditions and the preference by user characteristics in one-room housing. The data collected through questionnaire surveys from the residents of one-room housing in kangnam & sinchon. 259 samples we collected and are analyzed by using SPSS-PC. The results are follows : 1) Students: Students prefer monthly rent, down town, of officetel type, 8-l0py room size, and semi-furnished 2)Business men: They prefer multi function housing mixed office and residence, down town, officetel type, 11-l5py, and fully furnished housing. 3)Newly marriged couples: Ordinary habitation site, apt type, 16-l8py ,and 5: 5 division of space(bedroom:others) 4) Old age: normal habitation site, residence-commerce complex building type, middle corridor type, and 11-l5py. 5)Couple+child: lease of deposit basis, apt complex site, and 16-l8py.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.29A no.7
• /
• pp.10-18
• /
• 1992

In this paper, a simulation model for scope and filter parameters in CMIS/CMIP, OSI management protocol, has been discussed and the suitable scope type was represented by analyzing optimal polling time in network management system, queue size and response time. Scope and filter parameters in MGet, M-Set, M-Action, and =M-Delete services provide a scheme to select some managed objects, and the results are largely varied according to a scope type requested and the outcome of filtering. It has been simulated each scope type and all scope type mixed in a network by varying the offered load and a polling time. On the same time, the response time, queue size of the managing system and a delay time have been measured. As a results, the suitable scope type and polling time enhancing the network performance on the OSI network management is proposed.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.34 no.5 s.118
• /
• pp.32-38
• /
• 2006

Roof greening in a city can contributes to not only providing network opportunities for dispersed greenspace patches but also bringing more greenspaces into a city. In addition, it can help to flooding and microclimate control in the city. Recently, a number of roof greening projects have been introduced, mainly to public buildings and schools. Roof peening need to offers both ecological functions and convenience and satisfaction for urban residents. This study aims to provide directions for improving ecological benefits and visual preference of roof greening. Twelve scene slides were adopted to measure people's visual preference. The survey results show that landscape images can be categorized into naturalness, visual diversity, uniqueness, and spatial flexibility. Physical scenes can be classified into type I mostly greened by plants, type II mixed between convenience facilities and plants, and type III constructed with pond. People show high preferences to type I and type II when visual diversity is high. The results of this study suggest to enhance the visual preference by considering visual diversity when applying the ecological design methods to improve naturalness for roof greening.