• Nuclear Engineering and Technology
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• 제41권6호
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• pp.831-840
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• 2009

In order to evaluate the start-up behavior and to identify, through abnormal operation occurrences, the transient behaviors of the Sulfur Iodine(SI) process, which is a nuclear hydrogen process that is coupled to a Very High Temperature Gas Cooled Reactor (VHTR) through an Intermediate Heat Exchanger (IHX), a dynamic simulation of the process is necessary. Perturbation of the flow rate or temperature in the inlet streams may result in various transient states. An understanding of the dynamic behavior due to these factors is able to support the conceptual design of the secondary helium loop system associated with a hydrogen production plant. Based on the mass and energy balance sheets of an electrodialysis-embedded SI process equivalent to a 200 $MW_{th}$ VHTR and a considerable thermal pathway between the SI process and the VHTR system, a dynamic simulation of the SI process was carried out for a sulfuric acid decomposition process (Second Section) that is composed of a sulfuric acid vaporizer, a sulfuric acid decomposer, and a sulfur trioxide decomposer. The dynamic behaviors of these integrated reactors according to several anticipated scenarios are evaluated and the dominant and mild factors are observed. As for the results of the simulation, all the reactors in the sulfuric acid decomposition process approach a steady state at the same time. Temperature control of the inlet helium is strictly required rather than the flow rate control of the inlet helium to keep the steady state condition in the Second Section. On the other hand, it was revealed that the changes of the inlet helium operation conditions make a great impact on the performances of $SO_3$ and $H_2SO_4$ decomposers, but no effect on the performance of the $H_2SO_4$ vaporizer.

• Journal of Neurogastroenterology and Motility
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• 제24권4호
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• pp.512-527
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• 2018

This review provides a comprehensive overview of brain imaging studies of the brain-gut interaction in functional gastrointestinal disorders (FGIDs). Functional neuroimaging studies during gut stimulation have shown enhanced brain responses in regions related to sensory processing of the homeostatic condition of the gut (homeostatic afferent) and responses to salience stimuli (salience network), as well as increased and decreased brain activity in the emotional response areas and reduced activation in areas associated with the top-down modulation of visceral afferent signals. Altered central regulation of the endocrine and autonomic nervous responses, the key mediators of the brain-gut axis, has been demonstrated. Studies using resting-state functional magnetic resonance imaging reported abnormal local and global connectivity in the areas related to pain processing and the default mode network (a physiological baseline of brain activity at rest associated with self-awareness and memory) in FGIDs. Structural imaging with brain morphometry and diffusion imaging demonstrated altered gray- and white-matter structures in areas that also showed changes in functional imaging studies, although this requires replication. Molecular imaging by magnetic resonance spectroscopy and positron emission tomography in FGIDs remains relatively sparse. Progress using analytical methods such as machine learning algorithms may shift neuroimaging studies from brain mapping to predicting clinical outcomes. Because several factors contribute to the pathophysiology of FGIDs and because its population is quite heterogeneous, a new model is needed in future studies to assess the importance of the factors and brain functions that are responsible for an optimal homeostatic state.

• 융합정보논문지
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• 제8권6호
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• pp.101-106
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• 2018

전라북도 지역에 거주하는 성인들의 안위특성과 안정피로의 연관성을 조사하였다. 사시, 안질환 또는 전신질환이 없는 19세에서 55세까지의 비정시안 114명을 대상으로, 교정시력, 안경교정 굴절력, 융합여력검사, 사위검사를 실시하였으며, 사위방향 및 크기와 융합여력에 따른 안정피로 발생 빈도를 분석하였다. 114명 가운데 41명이 안정피로를 호소하였고 이 가운데 외사위는 69%, 내사위는 5.5%, 정위는 26% 였다. 근거리 측정에서 정상으로 간주되는 $0-6{\Delta}$의 외사위은 61.4%이었고, 정상범위 외의 사위는 대상안의 38.6%이었다. 융합여력의 크기는 사위량이 많을수록 적어졌으며, 융합여력이 사위량의 2배 이상인 사람이 27.2%이고 2배 미만인 사람이 72.8%로 조사되었다. Heterphoria 방법으로 측정한 AC/A는 최저 1.0에서 최대 12.6까지 분포하고 있었으며, 사위안의 안정피로와는 특별한 관계를 발견 할 수 없었다. 사위에서 유발되는 안정피로가 융합여력과 연관성이 있었으며, 사위안의 근거리 안경 교정을 위한 양안시 검사를 수행할 때 융합여력 검사를 수행해야 할 것으로 생각된다.

• 디지털융복합연구
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• 제17권3호
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• pp.221-226
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• 2019

뇌파 파형중 베타파를 이용한 인간의 인지상태를 판별한다. 베타파는 인간의 인지상태중 스트레스 영역에 해당하는 특성이 있고, 이 영역에서 스트레스의 오버대역폭을 추출하기 위해서 저대역폭과 고대역폭 사이의 베타파간 상관관계를 분석해야 한다. 그러므로 본 논문에서는 효과적으로 베타파 상관관계를 분석하고 추출하기 위해 비지도학습 머신러닝을 이용한 Kmean 클러스터링 분석모델을 제시한다. 제시된 모델은 베타파 영역을 유사한 영역의 클러스터 군으로 분류하고 해당 클러스터링 범주에서 이상파형을 판별한다. 이상파형 판별을 위해 클러스터군의 밀집도와 정상범주 이탈영역을 기준으로 스트레스 위험군을 판별하고 판별된 스트레스 위험군에 대한 대처방안을 제공할 수 있다. 제시된 모델을 활용하면 뇌파파형을 통한 인지상태의 스트레스 지수분별이 가능하고, 개인의 인지상태에 대한 관리 및 응용이 가능하다. 또한 스트레스와 오피스증후군을 갖는 사람들에게 뇌파관리를 통해 개인의 삶에 대한 질적 향상에 도움을 준다.

• Asian-Australasian Journal of Animal Sciences
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• 제32권6호
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• pp.896-903
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• 2019

Objective: Qianbei-Pockmarked goats are affected by a disorder locally referred to as 'Ruanguzheng Disorder', which is characterized by emaciation, lameness, muscular relaxation, stiffness of the extremities, and abnormal curvatures of the long bones. Our objective was to determine the relationship between the disorder and phosphorus deficiency. Methods: Tissue samples were collected from affected and healthy animals, while soil and herbage samples were collected from affected and healthy pastures. Biochemical parameters were determined using an automatic biochemical analyzer (OLYMPUS AU 640, Olympus Optical Co., Tokyo, Japan). Mineral contents in soil, forage, and tissue were determined using a Perkin-Elmer AAS5000 atomic absorption spectrophotometer (Perkin-Elmer, Norwalk, CT, USA). Results: The results showed that phosphorus contents in herbages from affected pastures were markedly lower than those from healthy areas (p<0.01), and the ratio of calcium to phosphorus in the affected herbages was 12.93:1. The phosphorus contents of wool, blood, tooth, and bone from affected animals were also markedly lower than those from healthy animals (p<0.01). Serum phosphorus values in affected animals were much lower than those in healthy animals, while serum alkaline phosphatase values from affected animals were markedly higher than those from healthy animals (p<0.01). Inorganic phosphorus values from affected animals were approximately half of that in the control group. Supplementation of disodium hydrogen phosphate prevented and cured the disorder. Conclusion: This study demonstrates that Ruanguzheng disorder in Qianbei-Pockmarked goats is primarily caused by phosphorus deficiencies in herbage due to fenced pastures and natural habitat fragmentation.

• 한국해양공학회지
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• 제34권6호
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• pp.454-460
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• 2020

In 2019, the Korean government announced the 3rd Basic Plan for Energy, which included expanding the rate of renewable energy generation by 30-40% by 2040. Hence, offshore wind power generation, which is relatively easy to construct in large areas, should be considered. The East Sea coast of Korea is a sea area where the depth reaches 50 m, which is deeper than the west coast, even though it is only 2.5 km away from the coastline. Therefore, for offshore wind power projects on the East Sea coast, a floating offshore wind power should be considered instead of a fixed one. In this study, a response analysis was performed by applying the analytical conditions of IEC61400-3-2 for the design of floating offshore wind power generation systems. In the newly revised IEC61400-3-2 international standard, design load cases to be considered in floating offshore wind power systems are specified. The upper structure applied to the numerical analysis was a 5-MW-class wind generator developed by the National Renewable Energy Laboratory (NREL), and the marine environment conditions required for the analysis were based on the Ulsan Meteorological Buoy data from the Korea Meteorological Administration. The FAST v8 developed by NREL was used in the coupled analysis. From the simulation, the maximum response of the six degrees-of-freedom motion and the maximum load response of the joint part were compared. Additionally, redundancy was verified under abnormal conditions. The results indicate that the platform has a maximum displacement radius of approximately 40 m under an extreme sea state, and when one mooring line is broken, this distance increased to approximately 565 m. In conclusion, redundancy should be verified to determine the design of floating offshore wind farms or the arrangement of mooring systems.

• 반도체디스플레이기술학회지
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• 제20권4호
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• pp.161-166
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• 2021

Errors in the semiconductor process are generated by a change in the state of the equipment, and errors usually arise when the state of the equipment changes or when parts that make up the equipment have flaws. In this investigation, we anticipated that aging of the mass flow controller in the plasma enhanced chemical vapor deposition SiO2 thin film deposition method caused a minute flow rate shift. In seven cases, fourier transformation infrared film quality analysis of the deposited thin film was used to characterize normal and pathological processes. The plasma condition was monitored using optical emission spectrometry data as the flow rate changed during the procedure. Preprocessing was used to apply the collected OES data to the artificial immune system algorithm, which was then used to process diagnosis. Through comparisons between datasets, the learning algorithm compared classification accuracy and improved the method. It has been confirmed that data characterized as a normal process and abnormal processes with differing flow rates may be discriminated by themselves using the artificial immune system data mining method.

• 한국방재안전학회논문집
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• 제15권3호
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• pp.23-29
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• 2022

최근 급증하는 이상기후의 영향으로 인하여 국지성 호우의 발생 빈도가 증가하고 있다. 이로 인하여 안전한 수자원 관리의 어려움이 증가하고 있으며, 인적 및 물적 피해가 늘어나고 있다. 국지성 호우로 인한 피해를 저감하기 위하여 다양한 대책방안을 수립하고 있으나 소규모 산지유역은 기본계획 수립 등의 부재로 인하여 어려움을 겪고 있다. 본 연구에서는 우리나라 국립공원 중 지리산 국립공원 중 유평유역을 대상으로 강우-유출모형을 활용한 침수 위험도 평가를 수행하였다. 지리산 유평유역은 재현빈도 50년 이상의 강우 발생 시, 홍수가 발생하는 것으로 모의 되었으며, 수공 구조물, 안전 시설물 및 탐방로에 대하여 위험성이 높게 나타나는 것을 확인하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권3호
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• pp.916-937
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• 2023

Most of the existing Distributed Denial-of-Service mitigation schemes in Software-Defined Networking are only implemented in the network domain managed by a single controller. In fact, the zombies for attackers to launch large-scale DDoS attacks are actually not in the same network domain. Therefore, abnormal traffic of DDoS attack will affect multiple paths and network domains. A single defense method is difficult to deal with large-scale DDoS attacks. The cooperative defense of multiple domains becomes an important means to effectively solve cross-domain DDoS attacks. We propose an efficient multi-domain DDoS cooperative defense mechanism by integrating blockchain and SDN architecture. It includes attack traceability, inter-domain information sharing and attack mitigation. In order to reduce the length of the marking path and shorten the traceability time, we propose an AS-level packet traceability method called ASPM. We propose an information sharing method across multiple domains based on blockchain and smart contract. It effectively solves the impact of DDoS illegal traffic on multiple domains. According to the traceability results, we designed a DDoS attack mitigation method by replacing the ACL list with the IP address black/gray list. The experimental results show that our ASPM traceability method requires less data packets, high traceability precision and low overhead. And blockchain-based inter-domain sharing scheme has low cost, high scalability and high security. Attack mitigation measures can prevent illegal data flow in a timely and efficient manner.

• 예술인문사회 융합 멀티미디어 논문지
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• 제7권2호
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• pp.175-188
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• 2017

RFID는 무선 주파수를 이용하여 대상(물건, 사람 등)을 식별할 수 있는 기술로서 다양한 분야에서 사용 중에 있다. 과거 국방 분야에 RFID를 도입하려는 시도가 있었지만, 특수한 상황에서의 낮은 인식률 및 RFID가 가지는 여러 제한점들을 극복하지 못하여 국방 분야에 RFID를 확산시키는데 실패했다. 따라서 본 논문은 현재 미래의 중요 기술로 꼽히는 사물인터넷 기술을 적용하여 RFID의 제한점을 극복할 수 있는 방법을 제안한다. 또한 이를 이용하여 국방 보안에 활용 가능한 네 가지 시나리오(헬스케어 밴드와 RFID, 신원식별 및 이상현상 탐지, 출입제어, 기밀문서 관리)를 제안한다. 이와 더불어 각 기술의 효과적 국방 적용과 보안 수준의 향상을 위해서 RFID와 사물인터넷에 대한 기본 특성과 보안 요구사항을 분석한다. 본 논문에 제안된 시나리오 구현을 통하여 군 장병의 건강상태를 확인할 수 있을 뿐만 아니라 출입 및 접근통제, 아군·적군 식별, 기밀 문서의 관리 등의 국방 보안 강화에 이바지 할 것으로 기대된다.