• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2006.05a
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• pp.283-286
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• 2006

안전한 네트워크를 운영하기 위해, 네트워크 침입 탐지에서 오탐지율은 줄이고 정탐지율을 높이는 것은 매우 중요한 일이다. 최근 얼굴 인식, 생물학 정보칩 분류 등에서 활발히 적용 연구되는 SVM을 침입탐지에 이용하면 실시간 탐지가 가능하므로 탐지율의 향상을 기대할 수 있다. 그러나 입력 값들을 벡터공간에 나타낸 후 계산된 값을 근거로 분류하므로, SVM만으로는 이산형의 데이터는 입력 정보로 사용할 수 없다는 단점을 가지고 있다. 따라서 이 논문에서는 데이터마이닝의 의사결정트리를 SVM에 결합시킨 침입 탐지 모델을 제안하고 이에 대한 성능을 평가한 결과 기존 방식에 비해 침입 탐지율, F-P오류율, F-N오류율에 있어 각각 5.6%, 0.16%, 0.82% 향상이 있음을 보였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.2
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• pp.172-180
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• 2013

In this paper, we propose an energy-efficient camera operating scheme to save energy which can be used for mass surveillance cameras. This technique determines how many cameras should be turned on in the consideration of the velocity vector of monitoring targets, which is acquired by DSRC object tracking, the model of the specification of installed cameras, and the road model of installed sites. Also, we address other techniques used to save energy for the surveillance system as well. Throughout performance evaluation, we demonstrate the excellence of our proposed scheme compared with previous approaches.

• Membrane Journal
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• v.23 no.6
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• pp.460-468
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• 2013

This study reviewed optimum dosage rate of coagulant and ability to remove dissolved organic carbon without sedimentation in conventional water purification plant. It was confirmed that floc formated by pre-treatment process was broken by impeller of booster pump. Optimum dosage rate of coagulant was 4 mg/L (as PACl 17%) for floc formation through blend, coagulation and after passing through the pump when turbidity of raw water was less than 10 NTU. And average removal rate of dissolved organic carbon was 43% at that time. Maximum removal rate of dissolved organic carbon was 48%, even though coagulation rate was increased gradually until 8 mg/L (as PACl 17%). So removal rate of dissolved organic carbon is not much improved even if dosage rage of coagulant increase. TMP of PVDF (polyvinylidene flouride) pressurized MF process without pre-treatment operated at 0.54 bar and TMP of PVDF pressurized MF process with pre-treatment operated at 0.41 bar.

• Journal of the Korea Society of Computer and Information
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• v.19 no.10
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• pp.197-205
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• 2014

This study set out to develop a logistics rationalization model to reduce logistics costs including return route costs by using open information systems that overcame the limitations of the old closed logistics systems by the corporations and applying the principle of freight car sharing among them. In recent years, information infrastructure that can be easily shared by many such as information networks, however, One of the causes of rising logistics costs is high empty transfer rates on return routes after goods are transported from the distribution center of each company to consumption sites, It is propose to promote logistic efficiency and innovation. The study especially identified a logistics rationalization plan by examining and analyzing the stages of transportation on the circulation route of a distribution system from the distribution center of a corporation to consumption sites and the empty transfer rates and their current state.

• Journal of Korea Port Economic Association
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• v.34 no.2
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• pp.69-82
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• 2018

The number of ships serviced at the container terminals in Busan is increasing by 2.9% per year. In spite of the increase in calling ships, there are no official records of waiting rate by the port authority. This study attempts to compare the theoretical ship waiting ratio and actual ship waiting ratio. The actual ship waiting ratio of container terminals is acquired from the 2014 to 2016 data of PORT-MIS and Terminal Operating System (TOS). Furthermore, methods and procedures to measure the actual ship's waiting rate of container terminal are proposed for ongoing measurement. In drawing the theoretical ship waiting ratio, the queuing theory is applied after deploying the ship arrival probability distribution and ship service probability distribution by the Chi Square method. As a result, the total number of ships waiting in a terminal for three years was 587, the average monthly service time and the average waiting time was 13.8 hours and 17.1 hours, respectively, and the monthly number of waiting ships was 16.3. Meanwhile, according to the queuing theory with multi servers, the ship waiting ratio is 31.1% on a 70% berth occupancy ratio. The reason behind the huge gap is the congested sailing in the peak days of the week, such as Sunday, Tuesday, and Wednesday. In addition, the number of waiting ships recorded on Sundays was twice as much as the average number of waiting ships.

• Korean Chemical Engineering Research
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• v.47 no.1
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• pp.133-140
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• 2009

This paper presents the experimental study to analyze the pressure and production behavior using depressurization and thermal methods in order to evaluate the hydrate productivity in the 2-D multi-well, plate-type apparatus which has 80 md permeability and 30% hydrate saturation. Injecting methane gas through multi-well allowed to set up the highly saturated hydrate system and combining two different sorts of sands made possible to build up the low permeability system. In this system, both depressurization and electric stimulation methods were applied. When operating pressure was low, according to the depressurization experiments results, the gas recovery was high, however strong pulses which appeared at initial stage of production would damage the operation system. Moreover, cases that hydrate reformed have occurred by endothermic reaction. We have conducted experiments four and six times for the depressurization magnitudes of 140 psi and 320 psi, respectively, to analyze production behavior for the method more in detail. For the cases that the depressurization magnitude was set as 140 psi, the unstable period appears in the results, but stabilized soon. In the experiment results for 320 psi the discontinuous and intermittent behavior has been observed. Thermal stimulation experiments was conducted with depressurizing 80 psi which is the case that shows stable behavior and low recovery. In the results, the gas recovery was high and the energy efficiency was low for long stimulating time. The energy efficiency and gas recovery increased for the soaking time of 1 minute after 2 minute-preheating. In the cases of which the soaking time exceeds 1 minute, energy loss by long soaking time caused low gas recovery and poor energy efficiency.

• The Transactions of the Korea Information Processing Society
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• v.3 no.1
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• pp.1-8
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• 1996

A conveyor system in corrugated manufacturing industry may be in charge of carriage/storage, and may control logistics flow and production activities of products in a manufacturing process which consists of corrugators, conveyors, and printer-slotter systems. It identifies problems that the conveyor system in this case study is overloaded and often operated manually. This research is to evaluate e the conveyor system though simulation model of technological evaluation beyond d eco-nomic and qualitative one. The rate of operation and the load of the conveyor system are used as parameters in the simulation. This paper suggests a direction to a new conveyor system implementation the basis of the results that are derived by new alternatives based on current model. The best alternative is supposed to be the number of conveyors and the operation times of the printer-slotter that may be increased at the same time.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.332-332
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• 2016

수공구조물 설계시 hardware와 software의 발달로 수리계산과 수치해석의 오차율이 감소함에 따라 수치해석을 이용하는 빈도가 높아지고, 신뢰도가 향상되고 있는 추세에 있다. 그러나 댐 설계에 있어 수위별 방유량 관계 검토시 수치해석값은 각 수위에 해당하는 몇 개의 유량값을 대응시켜 경향만 비교하고 수리계산 결과를 설계에 반영해 왔다. 이러한 방법은 여수로 주변에 인접구조물이 없고, 여수로 각 수문별 균등한 유량이 방류될 경우 문제가 되지 않지만, 여수로 직상류 지형에 만곡부나 지형적 특성이 여수로 방류에 영향을 미치거나, 취수탑 등 여수로에 인접한 수리구조물이 설치되어 접근수로에서 복잡한 유동을 형성하는 경우 각 문비마다 방류량의 분배율은 달라질 수밖에 없고, 수리계산 결과를 일괄 반영하기에는 오차가 증가할 수밖에 없다. 이에 본 연구에서는 댐 운영시 중요한 인자 중 하나인 수위-방류량 관계에 대하여 수치모형을 이용한 정밀한 분석을 통하여 댐 여수로 운영시 오차율을 저감시키고, 적용성을 향상시키는 방안을 검토하였다. 첫째, 수위별 방류량 관계 검토시 여수로 상류에서 일정한 시간에 따라 선형적으로 수위가 증가하도록 경계조건을 설정한 후 3차원 수치해석 모형의 Output data를 단위시간에 따라 수위와 방류량이 산정되도록 하고, 기존 검토 방식대로 각 수위별 모형을 steady 상태로 수행하여 비교분석하였다. 수리계산과 기존 방식, 본 연구에서 제시한 방법에 대한 오차율 검토 결과 오차는 3 % 이내로 검토되었다. 둘째, 수치해석을 이용하여 수위별 방류량 산정시 접근유속에 대한 영향을 받게 되므로 수리계산시 에너지 경사를 이용하여 수위값을 반영하지만, 수치해석을 이용하여 수위별 방류량 산정시 경계조건을 부여한 수위값을 반영하거나, 임의의 지점에서의 수위값을 반영하는 경우 등 일괄적이지 않은 수위값을 반영하여 오차율이 증가하는 경향이 있다. 따라서, 본 연구에서는 여수로 지점별 전수두를 측정하여 방류량 값을 산정하여 비교하였다.

• The Transactions of the Korea Information Processing Society
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• v.2 no.5
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• pp.807-813
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• 1995

This paper proposes a method to determine the optimal utilizations of the UNIX systems. This method is developed using the definition-the optimal utilization is the maximum allowable utilization. In other words, the optimal utilization is the maximum utilization that can be allowed by users while providing tolerable response time. As the tolerable response time increases, the optimal utilization increases. Therefore, the optimal utilization is obtained at the maximal value of tolerable response time. Our analysis shows tolerable response time is achieved when the average of the trivial response time is less than 0.24 seconds for a given service objective. It also shows the optimal utilization consists of three components-%wio, and %usr. By way of example, the optimal utilizations of a machine (IBM 3081) running under the UNIX operating system are computed are computed using the proposed method.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.10
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• pp.1035-1042
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• 2005

Granular Activated Carbon(GAC) is widely used in drinking water treatment. At S and B Water Treatment Plant, GAC is used in place of granular media in conventional rapid filters(GAC Filter-Adsorber) for removal of Disinfection By-products(DBPs). The primary focus of this study is on the performance of existing filter-adsorber, and their operation. It was found that F/A process removed turbidity as effective as sand system. The ratio of Hydrophobic DOM (HPO) and hydrophilic DOM (HPI) fraction in the raw water at S and B WTP was similar. Filter Adsorber presented earlier DOC breakthrough and steady state condition which was contributed by biodegradation during operation period. The removal efficiency of DBPs were used to evaluate the filter performance. The DBPs concentration of F/A treated water was below treatment goal level (THM < $80\;{\mu}g/L$, HAA < $60{\mu}g/L$). The removal efficiency of THM decreased rapidly during operation period. However, HAA were removed steadily regardless of the influent concentration of HAA. These results indicate that the removal of THM depend upon the adsorption mechanism while the removal of HAA depend upon biodegradation as well as adsorption. The decrease of adsorption capacity and characteristic value of GAC may be attributed to the effect of high organic loading, residual free chlorine, coagulants, manganese oxidants and frequently backwashing. This study has confirmed that Filter adsorber process can be considered as effective alternatives for the removal of DBPs, especially HAA.