• 한국토양환경학회지
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• 제3권3호
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• pp.3-10
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• 1998

토양의 산/염기 완충능은 토양-오염물질-공극수로 이루어진 시스템의 pH에 직접적인 영향을 미치므로 오염물질의 토양내 거동예측시에 많은 영향을 미치는 매우 중요한 토양의 성질이다. 본 연구는 이중확산층이론과 two layer electrostatic 흡착모델을 응용하여 토양의 산/염기 완충능의 이론모델을 유도하고 이 모델의 적용절차를 제시하였다. 산-염기 적정실험을 통하여 두 종류의 카올리나이트의 완충능을 실측하고 이를 본 연구에서 개발된 모델의 예측치와 비교하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(2)
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• pp.345-348
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• 2000

In this paper, We described the procedures to generate an input-output buffer information specification (IBIS) model in digital IC circuits. We gives the method to describe IBIS standard I/O for the characteristics of I/O buffer and to represent its electrical characteristics. The parameters of I/O structure for I/O buffer modelling are also referred, and an IBIS model for CMOS, TTL IC, ROM and RAM constructed amounts about 216. This IBIS model can be used to the simulation of signal integrity of high speed circuits in a PCB level.

• 한국물환경학회지
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• 제26권6호
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• pp.910-918
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• 2010

In recent years, riparian buffer system has been known as one of the effective best management practices. However, establishment of riparian buffer system in aspect of plant species and its position in the riparian buffer zone has not been investigated due to lack of efficient evaluation method for the analysis of water quality improvement with established riparian buffer system. To solve this problem, the SWAT-REMM prototype was developed by the researchers in Canada. But, SWAT-REMM model can not consider the $NO_3-N$ load into riparian buffer system through subsurface flow. Thus to solved this problem, Fortran code of SWAT-REMM model was modified. This modified SWAT-REMM system was applied to the Bonggok watershed. Three riparian buffer scenarios, 15 m, 10 m, 5 m width for tree and grass, were made to evaluate the effects of riparian buffer system on water quality improvement. Reduction efficiency of T-N by riparian buffer system of 15 m wide was the greatest (6 ~ 37%, depending on subwatershed characteristics) among 3 scenarios. It indicates that the reduction efficiency of T-N load has increasing-tendency, as buffer width increasing. The results obtained from the analysis showed that wide buffer zones are found to be more effective in reducing non-point pollutant than narrow buffer zones in the riparian buffer zone system. Hence, the SWAT-REMM model could be efficiently used for evaluation and design the most effective riparian buffer systems to reduce pollutant loads to the watershed although many limitations still exist in SWAT-REMM model.

• 한국환경복원기술학회지
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• 제9권5호
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• pp.22-31
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• 2006

AnnAGNPS model would be applied to simulate the pollutant removal capacity with the buffer strip in the Deachung reservoir watershed. In 2002, 2,270 tons of TN and 221 tons of TP were discharged from the nonpoint source pollutants in this watershed. During the rainy season, from June to September, 66.4% of TN and 71.9% of TP resulted from nonpoint source loads. AnnAGNPS model was also used to simulate the nutrients removal capacity from the buffer strip under the condition that the present landuse would be changed to forest. As the result of simulation, the removal rates of nutrients from the buffer strip of Daecheong reservoir watershed are 406 tons of TN, 39 tons of TP, which means reduction rates are TN 17.9%, TP 17.8%, respectively.

• 방사성폐기물학회지
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• 제21권2호
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• pp.225-234
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• 2023

In the design of HLW repositories, it is important to confirm the performance and safety of buffer materials at high temperatures. Most existing models for predicting hydraulic conductivity of bentonite buffer materials have been derived using the results of tests conducted below 100℃. However, they cannot be applied to temperatures above 100℃. This study suggests a prediction model for the hydraulic conductivity of bentonite buffer materials, valid at temperatures between 100℃ and 125℃, based on different test results and values reported in literature. Among several factors, dry density and temperature were the most relevant to hydraulic conductivity and were used as important independent variables for the prediction model. The effect of temperature, which positively correlates with hydraulic conductivity, was greater than that of dry density, which negatively correlates with hydraulic conductivity. Finally, to enhance the prediction accuracy, a new parameter reflecting the effect of dry density and temperature was proposed and included in the final prediction model. Compared to the existing model, the predicted result of the final suggested model was closer to the measured values.

• International Journal of Computer Science & Network Security
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• 제23권1호
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• pp.153-163
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• 2023

This study is situated in the context of intelligent transport systems, where in-vehicle devices assist drivers to avoid accidents and therefore improve road safety. The vehicles present in a given area form an ad' hoc network of vehicles called vehicular ad' hoc network. In this type of network, the nodes are mobile vehicles and the messages exchanged are messages to warn about obstacles that may hinder the correct driving. Node mobilities make it impossible for inter-node communication to be end-to-end. Recognizing this characteristic has led to delay-tolerant vehicular networks. Embedded devices have small buffers (memory) to hold messages that a node needs to transmit when no other node is within its visibility range for transmission. The performance of a vehicular delay-tolerant network is closely tied to the successful management of the nodes' transit buffer. In this paper, we propose a message transit buffer management model for nodes in vehicular delay tolerant networks. This model consists in setting up, on the one hand, a policy of dropping messages from the buffer when the buffer is full and must receive a new message. This drop policy is based on the concept of intermediate node to destination, queues and priority class of service. It is also based on the properties of the message (size, weight, number of hops, number of replications, remaining time-to-live, etc.). On the other hand, the model defines the policy for selecting the message to be transmitted. The proposed model was evaluated with the ONE opportunistic network simulator based on a 4000m x 4000m area of downtown Bouaké in Côte d'Ivoire. The map data were imported using the Open Street Map tool. The results obtained show that our model improves the delivery ratio of security alert messages, reduces their delivery delay and network overload compared to the existing model. This improvement in communication within a network of vehicles can contribute to the improvement of road safety.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1053-1056
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• 2008

An application of CSG (Constructive Solid Geometry) modeling technique in Machining Simulation is introduced in this paper. The current CSG model is based on z-buffer CSG Rendering Algorithm. In order to build a CSG model, frame buffers of VGA (Video Graphic Accelerator) should be used in term of color buffer, depth buffer, and stencil buffer. In addition to using CSG model in machine simulation Stock and Cutter Swept Surface (CSS) should be solid. Method to create a solid Cuboid stock and Ball-end mill CSS are included in the present paper. Boolean operations are used to produce the after-cut part, especially the Difference operation between Stock and CSS as the cutter remove materials form stock. Finally, a small program called MaSim which simulates one simple cut using this method was created.

• 한국방재학회 논문집
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• 제8권4호
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• pp.111-118
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• 2008

수변완충지대는 토지로부터 나오는 오염물질의 하천으로 직접유입을 차단하고 저감하는 역할을 한다. 하지만 현재까지 수변완충지대 설정에 따른 유역에서의 저감효과를 분석하는 사례는 부족한 실정이다. 본 연구에서는 SWAT모형을 이용하여 Arcview GIS상에 병성천 유역 모형을 구축하고 SWAT모형에서의 filter strip기능을 이용하여 수변완충지대 설정에 따른 토사 유출량의 변화를 살펴보았다. 모의결과 저감효과가 큰 곳을 살펴보면 대체적으로 토사유출량 관측지점인 유역 출구지점과 가까운 소유역에서 저감효과가 큰 것으로 보였다. 또한 수변완충지대의 폭을 달리하여 시나리오 분석을 수행한 결과 5-10 m의 수변완충지대 폭이 그 저감효율이 가장 큰 것으로 보였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권2호
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• pp.683-701
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• 2012

IEEE 802.11 standard has achieved huge success in the past decade and is still under development to provide higher physical data rate and better quality of service (QoS). An important problem for the development and optimization of IEEE 802.11 networks is the modeling of the MAC layer channel access protocol. Although there are already many theoretic analysis for the 802.11 MAC protocol in the literature, most of the models focus on the saturated traffic and assume infinite buffer at the MAC layer. In this paper we develop a unified analytical model for IEEE 802.11 MAC protocol in ad hoc networks. The impacts of channel access parameters, traffic rate and buffer size at the MAC layer are modeled with the assistance of a generalized Markov chain and an M/G/1/K queue model. The performance of throughput, packet delivery delay and dropping probability can be achieved. Extensive simulations show the analytical model is highly accurate. From the analytical model it is shown that for practical buffer configuration (e.g. buffer size larger than one), we can maximize the total throughput and reduce the packet blocking probability (due to limited buffer size) and the average queuing delay to zero by effectively controlling the offered load. The average MAC layer service delay as well as its standard deviation, is also much lower than that in saturated conditions and has an upper bound. It is also observed that the optimal load is very close to the maximum achievable throughput regardless of the number of stations or buffer size. Moreover, the model is scalable for performance analysis of 802.11e in unsaturated conditions and 802.11 ad hoc networks with heterogenous traffic flows.

• KSBB Journal
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• 제15권5호
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• pp.452-457
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• 2000

Buffer의 특성에 맞는 체류인자에 관한 모텔식을 얻기 위 해서는 buffer 9} 양이온의 농도에 관한 관련식을 실험으로 결 정해야 한다 또한 model 식에서 비이온과 음이온의 체류인 자를 나타내는 ko와 k의 값이 일정한 경향을 나타내고 있기 때문에 buffer의 농도와 modifier의 농도를 동시에 고려한 model 식이 가능하게 된다. 본 연구에서 제안한 모델식을 이용하여 임의의 buffer의 농도에 따른 시료의 체류시간을 예측할 수 있다. 이러한 모텔식을 이용하여 buffer를 이 용한 RP-HPLC의 분석 및 분리조건을 예측할 수 있고 시행 오차적인 방법보다 빠른 시간 내에 최적의 분석 및 분리조건 을 얻을 수 있다