• The KIPS Transactions:PartD
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• v.10D no.6
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• pp.927-934
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• 2003

Database query optimates the selectivety of a query to find the most efficient access plan. Multi-dimensional selectivity estimation technique is required for a query with multiple attributes because the attributes are not independent each other. Histogram is practically used in most commercial database products because it approximates data distributions with small overhead and small error rates. However, histogram is inadequate for a query with multiple attributes because it incurs high storage overhead and high error rates. In this paper, we propose a novel method for multi-dimentional selectivity estimation. Compressed information from a large number of small-sized histogram buckets is maintained using the discrete cosine transform. This enables low error rates and low storage overheads even in high dimensions. Extensive experimental results show adventages of the proposed approach.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.4
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• pp.445-452
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• 2007

This study was carried out to examine effect of post-chlorine dosage reduction by ozonation and GAC process in the field plant for 3years in the "G" water purification plant in Seoul. And it is to compare GAC with BAC process in removal effects of TOC, THMs, THMFP, $UV_{254}$. As a result, chlorine dosage of ozonation and GAC(=BAC) is less demand than GAC. Seasonal reduction of chlorine demand is from about 37% to 59% with BAC, and from 24 to 46% with GAC. Higher reduction in BAC could be achieved. The efficiency of chlorine demand reduction with ozonation was depending on the organic carbon removal. $UV_{254}$ concentration is less about 0.13~0.74L/mg.m in BAC than GAC. Therefore, the combination of ozonation and GAC was more effective in reducing post-chlorine than the single GAC. TOC was also monitored, and results show that a linear relationship between TOC and chlorine demand is appropriate under each treatment process. It means that removal of organic matter(TOC) from finished water is necessary to reduce post-chlorine dosage in clear well and to minimize order of chlorine in distribution systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.6C
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• pp.785-792
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• 2004

In this paper, we propose a fast and efficient method that improves the performance of embedded zerotree wavelet(EZW) algorithm introduced by Sharipo． In the EZW algorithm, two bits are allocated for a symbol, but it is inefficient for compression and the zerotree coding wastes much time at encoding. In this paper, in order to increase the efficiency of compression, it will be allocated a variable bit for a symbol at each subband. To reduce the encoding time, we use a backscan method and lifting scheme instead of filter bank in wavelet transform. Experimental result are shown that the algorithm suggested in this paper has a better performance about 0.3∼1.5㏈ PSNR while the encoding time was speeded up more than 2-10 times compared with the EZW algorithm.

• Aerospace Engineering and Technology
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• v.6 no.1
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• pp.245-254
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• 2007

The on-board telemetry system of KSLV-1 transmits telemetry signal for the launch vehicle and satellite to ground telemetry system in real time. In ground telemetry system, antenna system acquires telemetry signals and transfers these to data processing system. Data processing system processes and recordes telemetry data and distributes it to each mission operator in order to monitor it the operation goes well or not. This document describes the configurations and functions of data processing system designed for efficient and appropriate processing of telemetry data.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.956-959
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• 2005

The overall goal of this thesis is to develop a new algorithm based on the octree model for geometric and mechanistic milling operation at the same time. Most commercial machining simulators are based on the Z map model, which has several limitations in terms of achieving a high level of precision in five-axis machining simulation. Octree representation being a three-dimensional (3D) decomposition method, an octree-based algorithm is expected to be able to overcome such limitations. With the octree model, storage requirement is reduced. Moreover, recursive subdivision is processed in the boundaries, which reduces useless computations. To achieve a high level of accuracy, fast computation time and less memory consumption, the advanced octree model is suggested. By adopting the supersampling technique of computer graphics, the accuracy can be significantly improved at approximately equal computation time. The proposed algorithm can verify the NC machining process and estimate the material removal volume at the same time.

• Journal of the Korean Chemical Society
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• v.16 no.6
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• pp.361-368
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• 1972

The organic solvent mixture of 5 % trioctylamine and 5 % n-octyl alcohol in n-hexane could be loaded with tungsten to 62 g $WO_3$/1 whereas the amine alone could be loaded only to 37 g $WO_3$/1. Molecular interaction between amine and tungstate ion during the solvent extraction process and the synergistic effect of alcohol in enhancing the solubility of the amine-tungstate complex have been studied by NMR spectroscopy. Tungsten has been shown to be extracted as a polymeric tungstate ion into the organic phase to form a trioctyl ammonium polytungstate salt, which was more stabilized in the hydrocarbon medium by interacting with alcohol via hydrogen bonding between the tungstate ion and alcohol.

• Journal of the Korea Society of Computer and Information
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• v.13 no.7
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• pp.157-164
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• 2008

In this paper we suggest a scheduling algorithm that transmits periodic traffics efficiently in tree-structured wireless sensor networks (WSNs). The related research[l] showed the problems such as increasing the energy consumption and decreasing the data throughput as the depth of tree increases. To solve these problems. we use idle time slots and avoid the redundancy at data transmission. Also we suggest the algorithm that transmits the control packet when it is similar to a previously measured data. And if emergency data is occurred, our proposed algorithm transits that data in EDP(Emergency Data Period) for reducing the wait time. The proposed algorithm shows more data throughput and less energy consumption than that of the related research.

• Parasites, Hosts and Diseases
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• v.25 no.1
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• pp.7-12
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• 1987

The indirect fluorescent antibody(IFA) test was used to detect serum IgG and IgM antibodies to Trichomonas vaginalis in 31 vaginal trichomoniasis, 7 candidiasis and in 20 non-infected healthy women with antigen prepared from axonic culture of Trichomenas vaginalis isolated from vulvovaginitis patient. The results were as follows: 1. In 31 vaginal trichomoniasis the positive reactions of IgG antibody were 27 in the 1/8 dilution or higher and :l in the 1/4 dilution whereas in healthy women the reaction showed significantly low as in the 1/4 dilution or below. 2. The sensitivity and specificity of IFA test for IgG antibody to trichomonad antigen in this study were 87.1% and 100%, respectively. 3. No significant difference of IgM antibody levels between vaginal trichomoniasis and healthy women was observed. 4. No relation between the levels of IgG and IsM antibodies to trichomonad antigen by IFA test was observed. 5. No relation between the time lapse and the level of serum IgG antibodies in IFA test of vaginal trichomoniasis was regarded. In conclusion the present study suggests that IFA test in trichomoniasis could be a useful tool for detection of anti-trichomonad IgG antibodies and applicable as an immunodiagnostic method.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.3
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• pp.209-214
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• 2018

This paper suggests simple algorithm of facility location problem in perishable commodities that satisfy with minimum total transportation cost and within the transportation time constraint $L^*$. For this problem, Lee[4] suggests very complex algorithm that decides candidate facility locations, computes total transportation cost for each candidate facility location, then moving the location to optimal location for top two facilities. On the other hand, this paper simply determines the candidate facility locations within $L^*$ using subtree concept, and decides optimal minimal total transportation cost for top two locations in centralized area of required quantity using neighborhood concept.

• Journal of Sensor Science and Technology
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• v.1 no.2
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• pp.147-154
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• 1992

This paper describes the design of implantable 8-channel telemetering system to get physiological signals. The internal circuits of this system are designed not only to achieve as small size and low power dissipation as possible, but also to enable continuous measurement of physiological signals. Its main functions are to enable continuous measurement of physiological signals and to accomplish on-off power switching of an implantable battery by receiving appropriate command signals from an external circuit. To integrate implantable biotelemetry system, we performed layout of internal system using Lambda based $2{\mu}m$ n-well design rules. This system, used together with appropriate sensors, is expected to be capable of measuring and transmitting such significant parameters as pressure, pH, and temperature.