• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.236-241
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• 2007

Recently, in accordance with the cultural progress and the improvement of citizen's consciousness level, it is the real situation that the construction of small-scaled Multi-Purpose Hall where various cultural events could be performed, is on increasing. However, because the most of Multi-Purpose Hall had been designed and built up without any consideration on Acoustic Factor, many problems are on occurring thereat. Because those small-scaled Multi-Purpose Hall have been mostly used with the finishing material which contains a high degree of Acoustic Absorption indiscreetly, both diffusion and reflection of sound are not establishing properly, and since the reverberation of sound is very low, in case of musical performance by musical instrument, its sound hears too arid and stiff, there occurs some acoustic defect such as it becomes difficult for music appreciation with sufficient timbre, so that the capability improvement on the matter is urgently requiring situation. On this viewpoint, this Research has caught the Authenticity of the forecasted value and actually measured value using Acoustic Simulation on the subject of the small-scaled Multi-Purpose Hall, and then intended to propose the optimum acoustic condition on the basis of the Authenticity. As the result, it could be designed a Multi-Purpose Hall equipped with the satisfactory acoustic performance compare with the time before improvement, so that it is considered that such research result could be practically used as the fundamental material when design for other similar small-scaled Multi-Purpose Hall in the future.

• The Korean Journal of Applied Statistics
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• v.20 no.2
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• pp.387-394
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• 2007

This paper considers several stratification strategies for multivariate and multipurpose survey with several quantitative stratification variables. We propose three methods of stratification based on, respectively, the method of cumulative frequency square root which is the most popular one in univariate stratification, cluster analysis, and factor analysis followed by cluster analysis. We then compare the efficiency of those methods using the Dong-Eup-Myun data of the holding numbers of farming machines, extracted from the 2001 Agricultural Census. It turned out that the method based on cluster analysis with factor analysis would be a relatively satisfactory strategy.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.10
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• pp.1532-1539
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• 2017

The floating photovoltaic system is a new concept in the renewable energy technology. That is similar to land based photovoltaic technology except floating system. So the system needs buoyant objects, mooring, ect, besides modules and supports, and that is able to withstand in water level changes and wind strength. Therefore the floating photovoltaic system is much different from land photovoltaic system. K-water (Korea Water Resources Corporation) has been operating two floating photovoltaic system that's capacity is 100 kW and 500 kW respectively since in summer 2011 for commercial generation, and have construction project for 2,000 kW in Boryeong multipurpose Dam and other areas. Furthermore K-water was developing a tracking-type floating photovoltaic system at Daecheong multipurpose Dam and developed and installed an ocean floating photovoltaic demonstration plant at Sihwa Lake in October 2013 for R&D. In this paper, we introduce that structure of floating photovoltaic system include buoyant structure, mooring system and auxiliary device. Especially the rope which is in part of mooring should be always maintain tension under any water level. Also we explain about structure design concept to wind load in an every loading condition and a kind of structure materials and PV structure types used in water environment. Especially ocean floating PV system is affected by tidal current and typhoon. So there are considering the elements in design. Finally we compare with floating and land photovoltaic on power amount. As a result of that we verified the floating photovoltaic system is more about 6.6~14.2 % efficiency than a general land photovoltaic system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.1
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• pp.131-140
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• 1992

For a real-time flood forecasting and reservoir control problem of a multipurpose dam, the online acquisition of hydro-meteorological data and computerized analysis of the acquired data are absolutely necessary for the prompt decision of reservoir discharges which can minimize the possible damages and simultaneously maximize the utilization of the runoff. By introducing a man-machine interface such as condensed color graphics of the analyzed results, it is much easier and faster to transform the information to the decision maker who can decide the reservoir discharge. The newly developed PC-REFCON, which represents the PC based real-time flood forecasting and reservoir control, can easily handle the above problems by adopting a innovative decision support system. The system has three principal components of, a data base subsystem which acquires and manages real-time data, a model subsystem which forecasts the flood runoff and simulates the reservoir operation, and a dialogue subsystem which helps decision maker and system engineers using various graphics and tables with renovative methodologies. The developed PC-REFCON will be utilized from the coming Summer of 1992 for the flood control of all the nine multipurpose reservoirs in Korea.

• The Journal of the Korea Contents Association
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• v.5 no.3
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• pp.83-91
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• 2005

The digital signature can be verified and disavowed only with cooperation of the signer in 'undeniable signature scheme. A signed confidential document of a company can be copied and delivered to a rival company. If a conventional signature scheme is used to sign the document, it can be confirmed as authentic by verifying the signature without the signer's cooperation. However, if the company doesn't want the document to be verified as authentic by the rival company, it is recommended to use the undeniable signature scheme. Convertible undeniable signature scheme has additional property that the signer can convert undeniable signature to the ordinary one. The document signed by undeniable signature scheme that is no longer confidential can be opened to public use by converting the signature to the ordinary one. In this study, the efficient multipurpose convertible undeniable signature scheme based on El-Gamal signature scheme is proposed. The proposed scheme satisfies undeniable property and can convert undeniable signature to the ordinary one. The number of public keys and signatures are less than those of Boyar's convertible signature scheme. It also reduces the number of communication steps of the signature confirmation protocol.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.216-219
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• 1997

We are developing a portable multipurpose gamma counting and imaging probe that will be useful for many applications in nuclear medicine including radioimmunoguided surgery in the detection and treatment of malignant tumors. Any diagnostic information provided by CT, MRI, PET, SPECT or gamma camera imaging prior to surgery obviously is very important, but current techniques are limited in many instances. To overcome some of these limitations, the portable multipurpose gamma probe is being developed. The gamma probe consists of NaI(Tl) crystal with 1" dia $\times$ 0.5" thick and singlechannel photomultiplier tube (SC-PMT) for counting, and 3" dia $\times$ 0.375" and multichannel photomultiplier tube (MC-PMT) for imaging, nuclear instrument module (NIM), position circuits, interface, and PC. The energy resolution using Tc-99m was measured as 14% and the spatial resolution using 3mm dia green LED was measured as 2.9mm. These priliminary results indicate that the currently developing probe is very promising and could be very useful for many applications in nuclear medicine.

• The Transactions of the Korea Information Processing Society
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• v.4 no.5
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• pp.1297-1307
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• 1997

This paper presents a multimedia mail system which transmit and redeive multimedia mailing messges on Intemet.This mail system is an extension of the exsting e-mail system for multimedia uncluding,text,image,MPEG video,and binary data,The MIME(Multipurpose Intert Mail Extensions)format,which is an extension of REF-822 maill format,is used to reprssent multimedia,and SMTP(Simple Mail Transfer Protocol)is utilized as a mail transport prttocol.The IMAP(Intenet Mail Access Protcol)which privides more functions than the widely used POP(Post Office Protocol)is used as a mailbox retrival protocol.The mail client is complemented on a multimedia PC while the server is implemented on a UNIX system.In the mail system, a mail sending program allows a user to attach binary files such as Postscript files and MPEG compressed video,while a receiving program provides direct interface to application programs to play back received multimedia mail messages.

• Journal of Korea Water Resources Association
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• v.42 no.1
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• pp.1-8
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• 2009

In this study, based on the major activities which might have affected the ecological system of the Geum River, a conceptual model was proposed to guide scenario development for the eco-hydrological river evaluation. Also, an analysis method employing a set of models consisting, with other supporting programs, of KModSim for watershed network analysis and RAP for ecosystem analysis was developed for eco-hydrological river assessment. Then, hydrological analyses with various scenarios were conducted to examine the flow regime changes expected from the construction and operation of the Youngdam Multipurpose Dam (YMD) and Daecheong Multipurpose Dam (DMD) in the Geum River basin. The results indicated that the "Percentile 10" values for 10% exceeding time were decreased by 20.5% and 8.0% at Sutong downstream of YMD and Gongju downstream of DMD, respectively, while "Percentile 90" values for 90% exceeding time were increased by 56.3% and 340.8% at Sutong and Gongju, respectively, resulting in the reduction of the high flow variability typical for unregulated rivers in Korea. The results of eco-hydrological analyses will be presented in the following papers.

• Journal of the Korean Geographical Society
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• v.32 no.2
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• pp.217-228
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• 1997

A Study on individual Characteristics and Daily Activities of Housewives in the City of Kwangju. This study examines housewives' daily activities, focusing upon individual characteristics. The data used in this study are based on the fuestionaire survey, asking of personal trip for the weekdays and the weekend. Daily activities are classified into 7 categories and individual characteristics are revealed by age, occupation, a degree of education, number of family, and the residential environment. The results of this study are as follows: 1) The relations between daily activities and individual characteristics are influenced by housewife's occupation. Daily activities of housewives who have jobs are different from those who do not have jobs for a weekday as well as for a weekend. 2) Housewives' daily activities show very busy and vigorous on Saturday. 3) Housewives who are employed are willing to make mutipurpose trips on Saturday. 4) For a weekday, housewives' daily activities are inclined to make one cycle trip in a day, and the more trip cycles are, the more multipurpose trips are made. 5) The relationships between daily activities and individual characteristics show the pattern of WH, WLH, LHLH as it can be grouped.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.4
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• pp.1389-1400
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• 2013

This study developed an operating rule curve (ORC) for multipurpose water supply (irrigation and environmental water) in heightened agricultural reservoir. Among the 20 reservoirs in improvement project of agricultural reservoir dam heightening, the 4 representative reservoirs (Ungyang, Gungchon, Yongam and Unam) were selected for the study according to the analysis of statistical characteristics. Available environmental water supply amounts during irrigation and non-irrigation periods, which is the range from release restricted water level to high water level were estimated by water balance analysis using reservoir operation model. Reliability, resiliency and vulnerability criteria for water system performance were used to assess the multiple water supply capacity. The ORC was presented as the percentile rank for the daily reservoir water level from the results of reservoir operation using the past couple of decades weather data. The water levels for each percentile were divided into 3 buffer sections representing drought (5~25%), normal (25~75%), and flood (75~95%) year to operate the heightened agricultural reservoir with ORC.