• Bulletin of the Korean Chemical Society
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• v.19 no.11
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• pp.1217-1221
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• 1998

We present results of molecular dynamic (MD) simulations for the segmental motion of liquid n-heptadecane in order to investigate conformational transitions from one rotational isomeric state to another. The behavior of the hazard plots for n-heptadecane obtained from our MD simulations are compared with that for polymer of Brownian dynamics (BD) study. The transition rate at the ending dihedrals of the n-heptadecane chain is much higher than that at the central dihedrals. In the study of correlation between transitions of neighboring dihedrals, the large value of c2 implies that some 30% of the transitions of the second neighbors can be regarded as following transitions two bonds away in a correlated fashion. Finally the analysis of multiple transitions and the number of times occurred in the initial 0.005 ns are discussed.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.173-173
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• 2018

본 연구는 기상-수문 분야에서 고해상도 수문기상요소를 산출하기 위해 WRF-Hydro(Weather Research and Forecasting and Model Hydrological modeling extension package) 모형을 한반도 대상으로 구축하였다. 모형은 미국 대기 연구 국립센터(NOAA)에서 개발된 커뮤니티형 고해상도 예측모델이므로 미국 등에서 활발히 활용되기 시작하였으나 아직 우리나라 적용성에 대한 연구는 많지 않다. 본 연구에서는 WRF-Hydro 모형을 한반도에 적절히 사용하기 위해 표면유출, 보수깊이, 표면거칠기와 같은 파라미터를 보정하였다. WRF-Hydro는 지역 기상모형인 WRF와 연계하여 coupled WRF/WRF-Hydro 모형을 구동하였으며, 고해상도 유출값을 얻기 위해 미국 지질조사국(USGS)에서 제공한 HydroSHEDS(Hydrological data and map based on SHuttle Elevation Derivatives at multiple Scales)를 이용하였다. 본 연구에서는 관측된 유출값을 Markov Chain Monte Carlo(MCMC) 방법을 활용하여 모형값과 비교하여 파라미터 보정을 수행하였으며, 파라미터 보정된 WRF/WRF-Hydro를 활용해 한반도 과거 홍수 및 가뭄 사상을 모의하여 결과를 분석하였다.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.18 no.33
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• pp.123-134
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• 1995

After the introduction of ATM as a proper technology for B-ISDN, there have been many research efforts to realize ATM networks. But a computationally tractable modelling technique which reflects diverse characteristics of the ATM traffic accurately is not available yet. In this study, we try to establish an accurate but still convenient ATM traffic model. We first introduce the modelling technique for the voice traffic based on the fluid flow approximation. Then we present a traffic model for the mixed traffic from multiple video sources and voice sources. The video source model is based on the 3 state continuous time Markov chain. The accuracy of the model is demonstrated by some comparison results with respect to simulation.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.26 no.3
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• pp.50-57
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• 2003

In this paper, we consider an integrated inventory system where a single supplier purchases and processes raw materials in order to deliver finished goods to a single buyer for effective implementation of Just-In-Time purchasing. An integrated JIT lot-splitting model of facilitating multiple shipments in small lots is developed in a JIT purchasing environment. Also, an iterative solution procedure is developed to find the order quantity for the finished goods and raw materials, and the number of shipments between buyer and supplier. We show by example that the integrated policy adopted by both buyer and supplier in a cooperative manner can provide them a greater economic benefit than seeking the local optimal inventory policy independently.

• Archives of Pharmacal Research
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• v.24 no.6
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• pp.485-498
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• 2001

Helicobacter pylori is one of the most commonly encountered human pathogens. It has been shown to be closely associated with peptic ulcer disease (PUD), gastric adenocarcinoma, and the gastric mucosa-associated lymphoid tissue (MALT) that may lead to gastric lymphoma. The current diagnostic methods include histology, microbiological culture, classic serology unease activity detection, polymerase chain reaction (PCR) and stool antigen detection. Its treatment modality options are multiple; however, a triple regimen consisting of a proton pump inhibitor (PPI), and two antibiotics for 10 to 14 days is preferred. Drug resistance is a growing problem in this organism and new therapeutic options are currently limited .

• Annals of Geriatric Medicine and Research
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• v.22 no.4
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• pp.200-203
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• 2018

Strongyloides stercoralis is an intestinal nematode that occurs sporadically in temperate areas like Korea. People who are in the immunosuppressed state, over the age of 65 or under the corticosteroid therapy are at risk for developing Strongyloides hyperinfection syndrome. Acute respiratory distress syndrome (ARDS) with alveolar hemorrhage is a rare presentation of Strongyloides hyperinfection. A 78-year-old man had been irregularly injected corticosteroid on his knees, but did not have any immunosuppressive disease. He was initially diagnosed with ARDS and septic shock. Bronchoalveolar lavage (BAL) fluid was bloody and its cytology revealed helminthic larvae identified as S. stercoralis. Results of Cytomegalovirus polymerase chain reaction (PCR), Pneumocystis jirovecii PCR, and Aspergillus antigen testing of the BAL fluid were positive. The clinical progress quickly deteriorated with multiple organ failure, shock and arrhythmia, so he finally died. This is a rare case of ARDS in an older patient without any known immunosuppressive conditions, with alveolar hemorrhage and S. stercoralis being found via BAL.

• Korean Journal of Veterinary Research
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• v.60 no.4
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• pp.241-244
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• 2020

Three neonatal pigs from the same litter in a domestic farm were born with skin lesions. Grossly, multiple well-circumscribed, round papules distributed over the skin of the three piglets. Two piglets were submitted for a diagnosis of skin disease. Microscopically, epidermal hyperplasia with ballooning degeneration of stratum spinosum keratinocytes was observed. Some keratinocytes contained eosinophilic intracytoplasmic inclusions and a central nuclear vacuole and chromatin margination. Swinepox (SWP) virus was detected by polymerase chain reaction and nucleotide sequencing, and Staphylococcus hyicus was isolated in skin lesions. Based on the gross findings and laboratory results, these piglets were diagnosed with congenital SWP with a secondary staphylococcal infection.

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.861-869
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• 2023

This article proposes a novel approach to measure the performance of Safety-Critical Systems (SCS). Such systems contain multiple processing nodes that communicate with each other is modeled by a Petri nets (PN). The paper uses the PN for the performance evaluation of SCS. A set of ordinary differential equations (ODEs) is derived from the Petri net model that represent the state of the system, and the solutions can be used to measure the system's performance. The proposed method can avoid the state space explosion problem and also introduces new metrics of performance, along with their measurement: deadlock, liveness, stability, boundedness, and steady state. The proposed technique is applied to Shutdown System (SDS) of Nuclear Power Plant (NPP). We obtained 99.887% accuracy of performance measurement, which proves the effectiveness of our approach.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.1
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• pp.1-21
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• 2013

The release of IEEE 802.15.4e specification significantly develops IEEE 802.15.4. The most inspiring improvement is the enhancement for medium access control (MAC) sublayer. To study the performance of IEEE 802.15.4e MAC, in this paper we first present an overview of IEEE 802.15.4e and introduce three MAC mechanisms in IEEE 802.15.4e. And the major concern here is the Time Slotted Channel Hopping (TSCH) mode that provides deterministic access and increases network capacity. Then a detailed analytical Markov chain model for TSCH carrier sense multiple access with collision avoidance (CSMA-CA) is presented. Expressions which cover most of the crucial issues in performance analysis such as the packet loss rate, energy consumption, normalized throughput, and average access delay are presented. Finally the performance evaluation for the TSCH mode is given and we make a comprehensive comparison with unslotted CSMA-CA in non-beacon enabled mode of IEEE 802.15.4. It can validate IEEE 802.15.4e network can provide low energy consumption, deterministic access and increase network capacity.

• Journal of Ginseng Research
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• v.37 no.3
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• pp.361-370
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• 2013

A lysine histidine transporter (LHT) cDNA was isolated and characterized from the roots of Panax ginseng, designated PgLHT. The cDNA is 1,865 bp with an open reading frame that codes for a protein with 449 amino acids and a calculated molecular mass of 50.6 kDa with a predicted isoelectric point of 8.87. Hydropathy analysis shows that PgLHT is an integral membrane protein with 9 putative membrane-spanning domains. Multiple sequence alignments show that PgLHT shares a high homology with other plant LHTs. The expression profile of the gene was investigated by real-time quantitative polymerase chain reaction during various chemical treatments. PgLHT was up-regulated in the presence of abscisic acid, salicylic acid, methyl jasmonate, NaCl, and amino acids. To further explore the function of PgLHT gene, full-length cDNA of PgLHT was introduced into P. ginseng by Agrobacterium rhizogenes A4. The overexpression of PgLHT in the hairy roots led to an obviously increase of biomass compared to the controls, and after addition of the amino acids, the overexpressed-PgLHT hairy roots grew more rapidly than untreated controls during early stage of the culture cycle. The results suggested that the PgLHT isolated from ginseng might have role in the environmental stresses and growth response.