• Asian-Australasian Journal of Animal Sciences
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• 제30권3호
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• pp.299-308
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• 2017

Oxidative stress suppresses animal health, performance, and production, subsequently impacting economic feasibility; hence, maintaining and improving oxidative status especially through natural nutrition strategy are essential for normal physiological process in animals. Phytochemicals are naturally occurring antioxidants that could be considered as one of the most promising materials used in animal diets in various forms. In this review, their antioxidant effects on animals are discussed as reflected by improved apparent performance, productivity, and the internal physiological changes. Moreover, the antioxidant actions toward animals further describe a molecular basis to elucidate their underlying mechanisms targeting signal transduction pathways, especially through the antioxidant response element/nuclear factor (erythroid-derived 2)-like 2 transcription system.

• BMB Reports
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• 제56권4호
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• pp.209-215
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• 2023

Maintaining internal homeostasis and regulating innate behaviors are essential for animal survival. In various animal species, a highly conserved neuroendocrine system integrates sensory inputs and regulates physiological responses to environmental and internal changes. Diuretic hormones 44 and 31, which are homologs of mammalian corticotropin-releasing factor (CRF) and calcitonin gene-related peptide (CGRP), respectively, control body fluid secretion in Drosophila. These neuropeptides and their receptors have multiple physiological roles, including the regulation of body-fluid secretion, sleep:wake cycle, internal nutrient-sensing, and CO₂-dependent response. This review discusses the physiological and behavioral roles of DH44 and DH31 signaling pathways, consisting of neuroendocrine cells that secrete DH44 or DH31 peptides and their receptor-expressing organs. Further research is needed to understand the regulatory mechanisms of the behavioral processes mediated by these neuroendocrine systems.

• Carbon letters
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• 제16권3호
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• pp.203-210
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• 2015

This study fabricated low thermal conductive polyacrylonitrile (PAN)-based carbon fibers containing cellulose particles while maintaining their mechanical properties. The high thermal conductivity of carbon fibers limits their application as a high temperature insulator in various systems such as an insulator for propulsion parts in aerospace or missile systems. By controlling process parameters such as the heat treatment temperature of the cellulose particles and the amount of cellulose added, the thermal and mechanical properties of the PAN-based carbon fibers were investigated. The results show that it is possible to manufacture composite carbon fibers with low thermal conductivity. That is, thermal conductivities were reduced by the cellulose particles in the PAN based carbon fibers while at the same time, the tensile strength loss was minimized, and the tensile modulus increased.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.311-314
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• 2009

Recently by the development of the electronic engineering technology various mobile devices are developed. But their operation time need to be extended although capacity of the batteries are limited. We focused our attention to the portable SOFC system. Because SOFC has the high efficiency and a lot of strongness in comparison with other kinds of fuel cells, We evaluated hydrogen fed SOFC 50W system theoretically and got the results about the operating condition range from the comparison of the power efficiency, exhaust gas temperature, required heat for maintaining the operation temperature and operation time.

• 한국수소및신에너지학회논문집
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• 제34권5호
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• pp.490-496
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• 2023

Unmanned aerial vehicles (UAVs) research is recently actively underway. Especially, fuel cell battery hybrid systems are widely used to overcome the limitations of continuous operation. However, fuel cell systems must be operated in combination with a battery due to their low specific output characteristics. Therefore, a hybrid power system model for UAVs is developed. The rule-based strategy is applied to the model to properly distribute power to batteries and fuel cells. As a result, the designed rule-based power distribution control operates UAVs while maintaining battery state of charge(SOC) at an appropriate level.

• 산업기술연구
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• 제40권1호
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• pp.7-12
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• 2020

Lithium-ion cells have become the go-to energy source across all applications; however, dendritic growth remains an issue to tackle. While there have been various research conducted and possible solutions offered, there is yet to be one that efficiently rules out the problem without, however, introducing another. This paper seeks to present a fast charging method and system to which lithium-ion batteries are charged while maintaining their lifetime. In the proposed method, various lithium cells are charged under multiple profiles. The parameters of charge profiles that inflict damage to the cell's electrodes are obtained and used as thresholds. Thus, during charging, voltage, current, and temperature are actively controlled under these thresholds. In this way, dendrite formation suppressed charging is achieved, and battery life is maintained. The fast-charging system designed, comprises of a 1.5kW charger, an inbuilt 600W battery pack, and an intelligent BMS with cell balancing technology. The system was also designed to respond to the aging of the battery to provide adequate threshold values. Among other tests conducted by KCTL, the cycle test result showed a capacity drop of only 0.68% after 500 cycles, thereby proving the life maintaining capability of the proposed method and system.

• ETRI Journal
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• 제46권2호
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• pp.227-237
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• 2024

This study proposes a novel, conditionally applied neural network technique to reduce the overall peak-to-average power ratio (PAPR) of an orthogonal frequency division multiplexing (OFDM) system while maintaining an acceptable bit error rate (BER) level. The main purpose of the proposed scheme is to adjust only those subcarriers whose peaks exceed a given threshold. In this respect, the developed C-ANN algorithm suppresses only the peaks of the targeted subcarriers by slightly shifting the locations of their corresponding frequency samples without affecting their phase orientations. In turn, this achieves a reasonable system performance by sustaining a tolerable BER. For practical reasons and to cover a wide range of application scenarios, the threshold for the subcarrier peaks was chosen to be proportional to the saturation level of the nonlinear power amplifier used to pass the generated OFDM blocks. Consequently, the optimal values of the factor controlling the peak threshold were obtained that satisfy both reasonable PAPR reduction and acceptable BER levels. Furthermore, the proposed system does not require a recovery process at the receiver, thus making the computational process less complex. The simulation results show that the proposed system model performed satisfactorily, attaining both low PAPR and BER for specific application settings using comparatively fewer computations.

• Biomolecules & Therapeutics
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• 제32권4호
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• pp.403-423
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• 2024

The human gastrointestinal (GI) tract houses a diverse microbial community, known as the gut microbiome comprising bacteria, viruses, fungi, and protozoa. The gut microbiome plays a crucial role in maintaining the body's equilibrium and has recently been discovered to influence the functioning of the central nervous system (CNS). The communication between the nervous system and the GI tract occurs through a two-way network called the gut-brain axis. The nervous system and the GI tract can modulate each other through activated neuronal cells, the immune system, and metabolites produced by the gut microbiome. Extensive research both in preclinical and clinical realms, has highlighted the complex relationship between the gut and diseases associated with the CNS, such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. This review aims to delineate receptor and target enzymes linked with gut microbiota metabolites and explore their specific roles within the brain, particularly their impact on CNS-related diseases.

• 디자인학연구
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• 제12권4호
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• pp.61-68
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• 1999

국내 여건을 살펴볼 때, 상용 범용 소프트웨어나 멀티미디어 타이틀이 아닌 통신망 운용 관리라는 전문 영역에 HCI 디자인 개념을 적용하였다는 것은 상당히 의미하는 바가 크다고 할 수 있다. 가입자망 운용관리를 위한 시스템은 이미 80년대에 개발된 시스템으로 가입자로부터 전화시설의 고장 신고를 접수하고, 고장 여부를 시험하며, 그결과를 통보하는 기능을 주로 담당한다. 이번에 새로 개발되고 있는 시스템은 기존 가입자의 대다수를 차지하는 동선시설에 대한 운용관리 시스템의 기능을 수용하고, 관리 영역을 광 케이블 시설까지 확장한 새로운 운용관리 시스템이다. 또란 기존의 시스템은 80년대 텍스트 기반으로 구성된데 반하여 새롭게 개발되는 시스템은 윈도우 시스템을 기반으로 개발되고 있다. 따라서 사용자층의 변화와 개발환경의 변화는 사용자인터페이스 디자인 측면에 있어서도, 새로운 디자인의 기능성 및 제한점을 보여주고 있다. 첫째, 새로이 개발되는 시스템은 기존 시스템 운용자들이 새로운 운용관리 시스템을 사용할 때에 쉽게 적응할 수 있도록 디자인되어져야 하며, 둘째, 초보 운용자를 중심으로 윈도우 시스템에 기반을 두고 사용성이 현저히 개선되어져야 한다. 마지막으로, 시스템의 메뉴체계 구성 디자인을 위하여 시스템을 사용하는 운용자층을 그룹화하여 별도 요소로 관리할 필요가 있다는 점이다. 이 특이점들을 해결하기 위하여 1차적으로 전화국을 직접 방문하여 현장의 업무처리 내용정리. 동선 및 광선 가입자 전송결로 및 고장수리 업무절차, 이에 따른 각 기능별 Entity를 추출하는 업무분석과 사용자 분석이 이루어졌으며, 다음으로 기존 동선가입자에게 적용되어 사용하고 있는 시스템이 분석되어 졌다. 위 분석을 바탕으로 다양한 시스템 유저군별로 메뉴시스템 및 화면 구성이 이어졌다. 이로 인해 동선 시설 및 광케이블 시설에 대한 통합관리 인터페이스를 제공할 수 있게 되었으며, 각 기능별 업무를 정확히 정의함으로써 작업의 효율을 향상시킬 수 있었고 오히려 사용자 화면으로 비교해 볼때 화면의 갯수는 줄어들었나 더 많은 기능을 수용 할 수 있는 효과를 얻었다.

• 한국중재학회지:중재연구
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• 제13권2호
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• pp.263-290
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• 2004

Dispute plays a key role in maintaining the desirable performance of trade transaction. Although avoidance of disputes is always a priority, it is also important to prepare methods of dispute resolution which are efficient and economical. So, understanding of chinese dispute resolution system is a necessary requirement for successful business operation with chinese companies. This article analyzed and compared with the ways of trade disputes settlement system such as negotiation, mediation, arbitration and litigation in China in order to help the Korean traders who enter into business with the chinese companies to settle their disputes efficiently. This article suggests that two methods of negotiation and mediation are more likely to be effective than arbitration and litigation to resolve disputes with chinese companies because of problems of enforcement of arbitral award and the uncertainty of China's legal system.