• Proceedings of the Korea Society for Simulation Conference
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• 1992.10a
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• pp.8-8
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• 1992

Through a simulation experiment, often an experimenter is concerned with estimating the system parameters of the linear model consisting of m design points from the outputs oft the simulation model. To improve the estimation of the system parameters and reliability of these estimators, appropriate simulation techniques have been developed. For the first order linear model, Schruben and Margolin (1978) exploited the random number assignment rules which uses a combination of common random numbers and antithetic streams in a simulation experiment designed to estimate the system parameters when the design matrix of simulation model admits orthogonal blocking into two blocks. Nozari, Arnold and Pegden (1984) developed a method for appliying the method of control variates to the situation of the linear model having multiple design points. This talk deals with a different way of utilizing controls under the correlation induction strategy of Schruben and Margolin's to improve the simulation efficiency, and presents a procedure for obtaining the estimators of the system parameters analytically. Simulation results on a selected simulation model indicate a promising evidence that a proposed method may yield better results than Schruben and Margolin's method.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.384-394
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• 2005

Important characteristics of impinging sprays intersected by a strongly convective gaseous cross flows were experimentally investigated. The breakup processes due to different Weber and Reynolds numbers of liquid and gas streams were visually examined with quantitative measurements of breakup lengths, penetration heights, and droplet sizes. Snapshot images and spay data evidenced that, at lower jet Reynolds number the breakup processes portrays the atomization profiles similar to typical column breakup of single orifice jet. At higher jet Reynolds numbers, disintegration of jet stream is significantly expedited by strong momentum transported from strongly convective gaseous stream. The breakup length and penetration height decreased as the convective flow increase. From the bottom the wall up, the SMD measured the centerline increase. The maximum SMD appeared the top of the SMD distribution

• Journal of Korean Society on Water Environment
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• v.29 no.6
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• pp.790-798
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• 2013

Benthic macroinvertebrates are widely used as biological indicators for assessing the integrity of aquatic ecosystem. However, sampling has usually been done with fixed sample size due to time consuming and costly process. This study was conducted to find out the influence of sample size on the biological indices (H' DI, R1, J, EPT, ESB and BMI) of benthic macroinvertebrates. The 15 replicate samples were quantitatively collected from each 3 different site of two mountain streams in May, 2011. With the replicate data, we combined the abundance of each species with all the possible combinations of the sample size. Along with the increase of sample size, the number of species increased continuously and did not converge. BMI showed little difference whereas other biological indices increased or decreased.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.552-557
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• 1998

Sampling schemes are intended for use in situations where stream-flow data are collected regularly, but concentration data are collected during only a limited number of time periods. Estimating water pollutant loading considering sampling intervals is presented, and for illustrative purposes the criterion is applied to the sampling station HS#3 of the Balan-reservoir watershed which is located at the southwest of Suwon. The stratification is employed uniformly for all sampling strategies in that the strata boundaries are defined using the actual distribution of flow values and the selected nonexceedence probabilities to minimize inaccuracy. Ratio estimator for SS, T-N, and T-P were used in order to calculate the water pollutant loading. A sampling scheme incorporating stratified sampling with real-time of the sampling characteristics is found to give the appropriate estimate of the mass load.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.7
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• pp.71-79
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• 2012

Propose stream cipher Canon that need in Wireless sensor network construction that can secure confidentiality and integrity. Create Canon 128 bits streams key by 128 bits secret key and 128 bits IV, and makes 128 bits cipher text through whitening processing with produced streams key and 128 bits plaintext together. Canon for easy hardware implementation and software running fast algorithm consists only of simple logic operations. In particular, because it does not use S-boxes for non-linear operations, hardware implementation is very easy. Proposed stream cipher Canon shows fast speed test results performed better than AES, Salsa20, and gate number is small than Trivium. Canon purpose of the physical environment is very limited applications, mobile phones, wireless Internet environment, DRM (Digital Right Management), wireless sensor networks, RFID, and use software and hardware implementation easy 128 bits stream ciphers.

• Journal of Computing Science and Engineering
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• v.9 no.3
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• pp.134-141
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• 2015

In on-demand multimedia streaming systems, streaming techniques are usually combined with proxy caching to obtain better performance. The patch streaming technique has no start-up latency inherent to it, but requires extra bandwidth to deliver the media data in patch streams. This paper proposes a proxy caching technique which aims at reducing the bandwidth cost of the patch streaming technique. The proposed approach determines media prefixes with high patching cost and caches the appropriate media prefix at the proxy/local server. Herein the scheme is evaluated using a synthetically generated media access workload and its performance is compared with that of the popularity and prefix-aware interval caching scheme (the prefix part) and with that of patch streaming with no caching. The bandwidth saving, hit ratio and concurrent number of clients are used to compare the performance, and the proposed scheme is found to perform better for different caching capacities of the proxy server.

• Proceedings of the Membrane Society of Korea Conference
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• 1996.03a
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• pp.69-90
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• 1996

In the chemical industry, in the pharmaceutical industry, and in a number of other industries separation processes are necessary to separate and purify products and raw materials [1,2]. Separation processes are also widely used in other applications such as in recycling valuable materials from waste streams. Unit operations for separation processes can be classified in phase separation techniques and component separation techniques based on the nature of the feed mixtures to be separated. The former techniques are used for the separation of heterogeneous mixtures, in which the feed is already present in two or more separated phases on a micro-scale. The latter are suitable for the separation of homogeneous mixtures such as gaseous mixtures and mixtures of completely miscible liquids. tn these cases the separation into individual components is generally achieved by utilizing the differences in physico-chemical properties of components, and is much more difficult compared to phase separation techniques. Separation processes such as distillation, evaporation, liquid-liquid extraction, and crystallization belong to this class.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.395-406
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• 2005

Important characteristics of swirl sprays intersected by a strongly convective gaseous cross flows were experimentally investigated. The breakup processes due to different Weber and Reynolds numbers of liquid and gas streams were visually examined with quantitative measurements of breakup lengths, penetration heights, and droplet sizes. Snapshot images and spray data evidenced that, at lower jet Reynolds number the breakup processes portrays the atomization profiles similar to typical column breakup of single orifice jet. At higher jet Reynolds numbers, disintegration of jet stream is significantly expedited by strong momentum transported from strongly convective gaseous stream. The breakup length and penetration height decreased as the convective flow increase. From the bottom the wall up, the SMD measured the centerline first increases and then decreases before again increasing.

• Korean Journal of Plant Taxonomy
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• v.52 no.4
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• pp.251-254
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• 2022

Saxifraga cortusifolia Siebold & Zucc. (Saxifragaceae, sect. Irregulares, ser. Rufescentes), a species considered endemic along mountain streams throughout Honshu, Shikoku, and Kyushu in Japan, was discovered as a wild population in the Cheona Valley in Haean-dong, Jeju-si on Jeju-do Island of Korea. The population consisted of three subpopulations occupying narrow areas 10 × 10 m², 5 × 5 m², and 10 × 5 m² in size. The number of individuals in the three subpopulations was confirmed to exceed 100. Most of the individuals were on or below rocks at the edge of the valley. A morphological description, detailed photos, and a key to related taxa in Korea are presented.

• The Transactions of the Korea Information Processing Society
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• v.7 no.2S
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• pp.629-637
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• 2000

The content-based information retrieval for a multimedia database uses feature information extracted from the compressed videos. This paper presents an effective method to detect scene changes from compressed videos. Scene changes are detected with DC values of DCT coefficients in MPEG-1 encoded video sequences. Instead of decoding full frames. partial macroblocks of each frame, horizontal and vertical macroblocks, are decoded to detect scene changes. This method detects abrupt scene changes by decoding minimal number of blocks and saves a lot of computation time. The performance of the proposed algorithm is analyzed based on the precision and the recall. The experimental results show the effectiveness in computation time and detection rate to detect scene changes of various MPEG-1 video streams.