• Korean Journal of Construction Engineering and Management
• /
• v.10 no.6
• /
• pp.107-116
• /
• 2009

As the Fundamentals of Construction Business Act was revised in December 2004 and its implementing ordinances and enforcement regulations were adjusted in June 2005, the screening system of low price subcontracting has been an obligation to the public owners, having brought about arguments for and against since it enacted in 1983. The statutes for low price subcontracting have been reinforced from this year; for example, it underlines to submit to a project and builds an information network of subcontracting works. The system's original intention was that prevents shoddy and fraudulent constructions caused by low price subcontracting and precludes disturbances of fair trade by screening that whether it satisfies the conditions or not in advance. But, the criterion for the existing low price subcontracting has several issues having held up a true mirror to the real situation. It is arguable to discharge an important task with the primary purpose. This dissertation have researched the problem with a deposit of subcontract and the low price subcontracting basic rate are being used by the criteria for deciding whether it is a low price subcontracting or not, so showing the plan of reformation based on the findings, it wishes to contribute toward making the most of the system's essential intent.

• Journal of the Korean Solar Energy Society
• /
• v.31 no.2
• /
• pp.82-88
• /
• 2011

The artificial increase in the solar intensity incident on solar cells using lenses or mirrors can allow solar cells to generate equivalent power with a lower cost. There are two types of concentration optics for solar energy conversion. One is to use mirrors, and the other is to use Fresnel lenses. The gains that can be achieved with a Fresnel lens or a parabolic mirror are compared. The result showed the gains are comparable and the two configurations were developed competitively. In application areas of Fresnel lenses as solar concentrators, several variations of design were devised and tested. Some PV systems still use commercially available flat Fresnel lenses as concentrators. A convex linear Fresnel lens to improve the concentration ratio and the efficiency is devised and flat linear Fresnel lens in thermal energy collection is utilized. In this study, we designed and optimized flat Fresnel lens and the 'light pipe' to develop 500X concentrated solar PV system. In the process, we compare the transmission efficiencies according to groove types. We performed rigorous ray tracing simulation of the flat Fresnel lenses. The computer aided simulation showed the 'grooves in case' has the better efficiency than that of 'grooves out case'. Based on the ray-trace results we designed and manufactured sample Fresnel lenses. The optical performance were measured and compared with ray-trace results. Finally, the optical efficiency was measured to be above 75%. All the design and manufacturing were performed based on that InGaP/InGaAs/Ge triple junction solar cell is used to convert the photon energy to electrical power. Field test will be made and analyzed in the near future.

• (The) Research of the performance art and culture
• /
• no.19
• /
• pp.281-315
• /
• 2009

Korean traditional music has been a process art which has been changed and re-created by musicians to mirror the musical aesthetics of contemporary people. Form court music, which has tried to keep the "authentic" form as much as possible, to folk music, which is closely associated to the people's life style, traditional music has expressed the life of the Korean people. From the early 20th century, traditional music faced a totally new music culture due to the Japanese annexation and rapid westernization. A new music network was established by modern theater and broadcast system. Many gayageum (12-stringed zither) masters were able to develop their own music in this new music culture. Female musicians came to exist because of a new music education system, called gwonbeon (school for female entertainers). Due to the rapid westernization, traditional music was becoming 'extinct'. The government's new system of Intangible Cultural Heritage tried to preserve traditional culture. Traditional music came to revive but became fossilized in order to preserve the 'archetype'. The so-called Living Human Treasures took power and became a social problem. The modern school education system was one of major factors for promotion of traditional music. However, it became one of main reasons for musicians to lose their musical creativity. Today, many performers and composers try to make a new composition and renovated musical instruments to suit the contemporary musical aesthetics.

• The Bulletin of The Korean Astronomical Society
• /
• v.40 no.1
• /
• pp.52.3-53
• /
• 2015

The GMT-Consortium Large Earth Finder (G-CLEF) is a fiber-fed, optical band high dispersion echelle spectrograph that selected as the first light instrument for the Giant Magellan Telescope (GMT). This G-CLEF has been designed to be a general- purpose echelle spectrograph with the precisional radial velocity (PRV) capability of 10 cm/sec as a goal. The preliminary design review (PDR) was held on April 8 to 10, 2015 and the scientific observations will be started in 2022 with four mirrors installed on GMT. We have been participating in this preliminary design study in flexure control camera (slit monitoring system), calibration lamp sources, dichroic assembly and the fabrication of the proto-Mangin Mirror. We present the design concept on the parts KASI undertaken, introducing the specifications and capabilities of G-CLEF.

• The Journal of the Acoustical Society of Korea
• /
• v.36 no.6
• /
• pp.378-386
• /
• 2017

Accurate distance measurement between maneuver target in underwater and measuring devices is required to perform quantitative test evaluation in marine weapons system R&D process. In general, the target distance is measured using a one-way ToA (Time of Arrival) method that calculates the time difference between transmitted and received signals from the two accurately synchronized devices. However, the distance estimation performance is degraded because of the multi-path environments. In this paper, the time-variant transfer function of complex underwater environment is estimated from each received data frame using RBD (Ray-based Blind Deconvolution), and the estimated time-variant transfer function is then used to get rid of the effect about complex underwater environment and to recover the data signal using PTRM (Passive Time Reversal Mirror). The result from the simulation and experimental data show that the suggested method improve the distance estimation performance when comparing with the conventional ToA method.

• The Journal of the Society of Korean Medicine Diagnostics
• /
• v.19 no.3
• /
• pp.151-158
• /
• 2015

Objectives Syndrome differentiation and treatment (辨證論治) is one of the core theories in Korean medicine and syndrome differentiation (辨證) constitutes a branch of disease diagnosis in Korean medicine. Yoon Gil-Young, one of the modern outstanding scholar of basic medical science in Korean medicine, wrote on basic theories of Korean medicine such as physiology, pathology, formula science, etc. Hereby we will analyze and discuss his works to understand his recognition of historical changes in the syndrome differentiation. Methods We conducted researches into the two works of Yoon Gil-Young's, which are "The Clinical Formula Science of Eastern Medicine (東醫臨床方劑學)" and "The theory of Four-Constitution Medicine (四象體質醫學論)". From Yoon's academic standpoint which connects the basic medical science with the clinical medicine, we analyzed his opinion about syndrome differentiation and its historical changes. Results According to Yoon's research work on syndrome differentiation and its historical changes, the development of syndrome differentiation, which goes in harmony with the history of Korean medicine, has its deep root in " Huangdi's Internal Classic (黃帝內經)" and "Treatise on Cold Damage and Miscellaneous Diseases (傷寒雜病論)". And through "Treatise on the Spleen and Stomach (脾胃論)" and the articles of warm disease (溫病論), the theory of syndrome differentiation became extended to the whole clinical diagnostic field in Korean medicine, finally including the achievements in "Treasured Mirror of Eastern Medicine (東醫寶鑑)", "Longevity and Life Preservation in Eastern Medicine (東醫壽世保元)". Conclusions Yoon Gil-Young recognized that the system of syndrome differentiation was developed in accordance with the theories from the "Treatise on Cold Damage and Miscellaneous Diseases", then the "Treatise on the Spleen and Stomach" and the articles of warm disease. The four-constitution medicine in Korea and Koho school in Japan which lays emphasis on abdominal signs also contributed to its development. Syndrome differentiation can be categorized basically into three states of intrinsic cold (本寒), intrinsic deficiency (本虛), intrinsic heat (本熱) according to the deficiency and excess in human body metabolism.

• Journal of Korean Medical classics
• /
• v.30 no.3
• /
• pp.11-40
• /
• 2017

Purpose : The purpose of this article is to make a clarification that Hwang Doyeon(黃度淵) was a official doctor(醫官) who even served as royal doctor(御醫), rather than merely a general doctor who worked in the private sector. The article also attempts to give a new perspective on the medical history about the late period of Joseon(朝鮮) Dynasty. Methods : In researching Hwang Doyeon's master work, the Gains and Losses of Medical Orthodoxy(醫宗損益), the article looks at his clinical medicines. Analyzing the historical records, the article makes an assumption that Hwang Doyeon and Hwang Dosoon(黃道淳), who was selected as an officer to discuss medicine with other medical officers(議藥同參), are the identical person. On this assumption, the article tries to reinterpret the medicine during the later Joseon Dynasty period. Result & Conclusion : The records, including the royal medical treatment records of the Gains and Losses of Medical Orthodoxy, the Daily Records of Royal Secretariat(承政院日記), the genealogy of Changwon Hwangs(昌原黃氏世譜), academic paper and government documents released posthumously, demonstrated that Hwang Doyeon and Hwang Dosoon are the same person. If so, we can have new historical interpretation about medical history of late Joseon Dynasty. First, during the late of Joseon Dynasty, there was an official and active medical knowledge interaction between government and private sector. Second, the Joseon's medicine has been established its own medical system based on the Treasured Mirror of Eastern Medicine(東醫寶鑑), trying to cope with cholera and other contemporary epidemics without relying on Chinese warm disease(溫病) medicine. Third, the Compilation of Formulas and Medicinals(方藥合編), is regarded not only as a must-read medical reading for medical doctors, also playing an important role on popularization of Korean medical knowledge.

• Journal of the Korean Solar Energy Society
• /
• v.32 no.5
• /
• pp.41-51
• /
• 2012

Heliostat field is the most important subsystem in the tower type solar thermal power plant since its optical performance affects the total system efficiency most significantly while the construction cost of it is the major part of total construction cost in such a power plant. Thus a well designed heliostat field to maximize the optical efficiency as well as to minimize the land usage is very important. This work presents methodology, procedures and result of heliostat filed design for 200kW solar thermal power plant built recently in Daegu, Korea. A $2{\times}2(m)$ rectangular shaped receiver located at 43(m) high and tilted $28^{\circ}$ toward heliostat field, 450 of heliostats of which the reflective surface is formed by 4 of $1{\times}1(m)$ flat plate mirror facet, and the land area having about $140{\times}120(m)$ size are used to form the heliostat field. A procedure to deploy 450 heliostats in radial staggered nonblocking formation is developed. Also the procedures to compute the cosine effect, intercept ratio, blocking and shading ratio in the field are developed. Finally the heliostat filed is designed by finding the optimal radial distance and azimuthal spacing in radial staggered nonblocking formation such that the designed heliostat field optical efficiency could be maximized. The designed heliostat field has 77% of annual average optical efficiency, which is obtained by annually averaging the optical efficiencies computed between the time of where sun elevation angle becomes $10^{\circ}$ after sunrise and the time of where sun elevation angle becomes $10^{\circ}$ before sunset in each day.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.751-755
• /
• 2005

We propose a sound source localization method using the Head-Related-Transfer-Function (HRTF) to be implemented in a robot platform. In conventional localization methods, the location of a sound source is estimated from the time delays of wave fronts arriving in each microphone standing in an array formation in free-field. In case of a human head this corresponds to Interaural-Time-Delay (ITD) which is simply the time delay of incoming sound waves between the two ears. Although ITD is an excellent sound cue in stimulating a lateral perception on the horizontal plane, confusion is often raised when tracking the sound location from ITD alone because each sound source and its mirror image about the interaural axis share the same ITD. On the other hand, HRTFs associated with a dummy head microphone system or a robot platform with several microphones contain not only the information regarding proper time delays but also phase and magnitude distortions due to diffraction and scattering by the shading object such as the head and body of the platform. As a result, a set of HRTFs for any given platform provides a substantial amount of information as to the whereabouts of the source once proper analysis can be performed. In this study, we introduce new phase and magnitude criteria to be satisfied by a set of output signals from the microphones in order to find the sound source location in accordance with the HRTF database empirically obtained in an anechoic chamber with the given platform. The suggested method is verified through an experiment in a household environment and compared against the conventional method in performance.

• Journal of the Korean Institute of Telematics and Electronics C
• /
• v.36C no.10
• /
• pp.8-16
• /
• 1999

This paper presents a new simulation-based analog cell synthesis approach with improved simulation efficiency For the hierarchical synthesis of analog cells we developed the sub-circuit optimizers such as current mirror and differential input stage. Each sub-circuit optimizer can be used for synthesis of analog cells such as OTA(operational transconductance amplifier), 2-stage OP-AMP and comparator. To reduce the time spending of the simulation-based synthesis we propose 2-stage searching scheme and simulation data reusing scheme. With those schemes the synthesis time spending of OTA was reduced from 301.05sec to 56.52sec by 81.12%. Since our synthesis system doesn't need other additional physical parameters except SPICE parameters, and is independent of the process and its model level, the time spending to port to other process is minimized. We synthesized OTA and 2-stage OP-AMP respectively with our approach to show its usefulness.