• 대한토목학회논문집
• /
• 제42권4호
• /
• pp.493-499
• /
• 2022

하수처리장의 방류수 수질기준이 강화되고 있으며, 이에 따라 하수처리장 시설도 고도화되고 있다. 또한 하수처리장의 방류수질은 높은 수준으로 유지되어야 하며, 이에 따라 효율적인 하수처리장 운영이 매우 중요한 이슈로 대두되고 있다. 본 연구에서는 하수처리장의 Blower Control Loigc 개발을 위해, 하수도 시설기준의 기본 송풍량 산정 방식을 기반으로 유입수질에 따른 필요 산소량 및 송풍량을 산정하였다. 본 연구를 통해 A 하수처리장의 실제 4월 수질 데이터를 적용하여 송풍량을 산정한 결과, 평균적으로 약 12 %의 송풍량이 절감이 될 수 있다는 것을 확인하였다. 본 연구에서 산정한 결과에 따라 Blower Control Logic을 개발하여 실제 하수처리장에 적용하게 된다면, 유입수질을 기반으로 송풍량 제어가 가능함에 따라 운전자의 경험에 의존하고 있는 기존의 하수처리 운영방식에서 벗어나 하수처리장 자율제어가 가능할 것으로 판단된다. 또한, 송풍량 및 전력비 절감이 이루어진 효율적인 하수처리장 운영을 기대 할 수 있으며, 이를 통해 불필요한 에너지 및 탄소 절감에 기여할 수 있을 것이라고 판단된다.

• 환경생물
• /
• 제40권2호
• /
• pp.164-171
• /
• 2022

꽃노랑총채벌레(Frankliniella occidentalis)는 500종 이상의 기주를 가지고 토마토반점위조바이러스(Tomato spotted wilt virus; TSWV)를 매개하는 해충이다. 전 세계적으로 방제를 위해 노력하고 있지만 살충제를 이용한 방제는 저항성 그리고 환경 및 경제적 부담으로 인한 한계를 보였기 때문에 고정 정확도를 설정한 표본조사법(Fixed-precision level sampling plan)을 개발하였다. 고추(Capsicum annuum)의 꽃노랑총채벌레 성충 방제를 위한 표본 조사법은 공간분포분석, 표본추출 정지선 그리고 의사결정법으로 구성되었다. 표본추출은 식물체를 상단(지상에서 180 cm 이상), 중단(지상에서 120~160 cm 이상), 하단(지상에서 70~110 cm 이상)으로 나누어 각 높이별로 꽃 3개에서 나오는 꽃노랑총채벌레의 성충의 마리 수를 조사하였다. 표본 추출을 통해 꽃노랑총채벌레 성충의 밀도는 다른 식물체 위치(중단, 하단)보다 상단에서 높은 것으로 나왔다. 공간분포분석에서는 Taylor's power law (TPL)를 통해 도출한 각 위치별 계수를 공분산분석(ANCOVA)하여 차이를 비교하였다. ANCOVA 결과에서 도출된 절편과 기울기의 P 값이 각각 0.94, 0.87인 것을 통해 식물체 내 위치별로 차이가 없음을 확인한 후, 자료를 통합(pooling)하여 계산된 TPL 계수를 이용하여 표본추출 정지선을 구하였다. 꽃노랑총채벌레의 방제의사결정을 위한 방제밀도 수준(m₀)은 문헌을 참조하여 3과 18로 설정하였으며 설정값(m₀)을 이용해 최대표본수(N_max)도 조사하였다. 조사 결과, m₀=3, 18일 때 N_max값은 각각 약 97개, 1149개로 계산되었다. 개발된 모델의 적합성 검정을 위해 분석에 사용하지 않은 독립자료를 이용해 Resampling Validation for Sampling Program (RVSP) 프로그램으로 개발된 표본추출법의 적합성 평가를 실시하였고 적합한 정확도를 보이는 것으로 조사되었다.

• 안보군사학연구
• /
• 통권7호
• /
• pp.271-303
• /
• 2009

"Ubiquitous sensor network" definition is this-Someone attaches electro-magnetic tag everything which needs communication between man to man, man to material and material to material(Ubiquitous). By using attached every electro-magnetic tag, someone detects it's native information as well as environmental information such as temperature, humidity, pollution and infiltration information(Sensor). someone connects it realtime network and manage generated information(Network). 21st century's war is joint combined operation connecting with ground, sea and air smoothly in digitalized war field, and is systematic war provided realtime information from sensor to shooter. So, it needs dramatic development on watch reconnaissance, command and control, pinpoint strike etc. Ubiquitous computing and network technologies are essential in national defense to operate 21st century style war. It is possible to use many parts such as USN combined smart dust and sensor network to protect friend unit as well as to watch enemy's deep area by unmanned reconnaissance, wearable computer upgrading soldier's operational ability and combat power dramatically, RFID which can be used material management as well as on time support. Especially, unmanned watch system using USN is core part to transit network centric military service and to get national defense efficiency which overcome the dilemma of national defense person resource reducing, and upgrade guard quality level, and improve combat power by normalizing guardian's bio rhythm. According to the test result of sensor network unmanned watch system, it needs more effort and time to stabilize because of low USN technology maturity and using maturity. In the future, USN unmanned watch system project must be decided the application scope such as application area and starting point by evaluating technology maturity and using maturity. And when you decide application scope, you must consider not only short period goal as cost reduction, soldier decrease and guard power upgrade but also long period goal as advanced defense ability strength. You must build basic infra in advance such as light cable network, frequency allocation and power facility etc. First of all, it must get budget guarantee and driving force for USN unmanned watch system project related to defense policy. You must forwarded the USN project assuming posses of operation skill as procedure, system, standard, training in advance. Operational skill posses is come from step by step application strategy such as test phase, introduction phase, spread phase, stabilization phase and also repeated test application taking example project.

• 한국산학기술학회논문지
• /
• 제18권12호
• /
• pp.390-399
• /
• 2017

본 논문은 유아교사의 행복감이 자아탄력성과 직무열의에 미치는 영향에 대해 알아보는 것이다. 본 연구의 대상은 K와 D지역에 소재한 유아교육기관에 근무하는 유아교사 243명이다. 연구 수집된 자료는 SPSS 18.0 프로그램을 이용하여 기술통계, 상관분석 및 회귀분석을 시행하였다. 본 연구의 결과는 다음과 같다. 첫째, 유아 교사의 행복감, 자아탄력성, 직무열의의 수준은 모두 높게 나타났다. 둘째, 유아교사의 행복감, 자아탄력성, 직무열의 간에는 통계적으로 유의미한 상관관계가 있는 것으로 나타났다. 셋째, 자아탄력성에 대한 행복감의 설명력은 18%였으며, 자아탄력성의 하위요인인 자아수용이 영향을 미치는 것으로 나타났다. 또한 유아교사의 직무열의에 대한 행복감의 설명력은 활력 23%인 것으로 나타났으며, 직무열의 활력의 하위요인인 자아수용, 긍정적 대인관계, 환경에 대한 지배력 순으로 영향을 미치는 것으로 나타났다. 그리고 유아교사의 전념에 대한 행복감 요인들의 설명력은 17%로 나타났고, 자아수용, 긍정적 대인 관계가 교사의 전념에 유의미한 정적 영향을 미치는 것으로 나타났다. 마지막으로 유아교사의 몰두에 대한 행복감 요인들의 설명력은 14%로 나타났고, 교사의 행복감 요인 중에서는 자아수용이 교사의 몰두에 유의미한 정적 영향을 미치는 것으로 나타났다. 본 연구 결과는 질 높은 유아교육의 보장과 유아들의 행복을 위해서는 우선 무엇보다 유아교사의 행복감이 증진되어야하며, 이는 나아가 자아탄력성과 직무열의의 향상을 위한 긍정적인 요인이 될 수 있음을 시사한다.

• 한국통신학회논문지
• /
• 제31권10A호
• /
• pp.1003-1013
• /
• 2006

IEEE802.11g VoWLAN (Voice over Wireless LAN) 단말기는 802.11b 전용 단말기에 비해 통화시간이 30 % 이상 감소하는 문제점이 있어 통화시간이 문제로 대두되고 있다. 일반적으로, 802.11g에서는 멀티캐리어 방식인 OFDM (Orthogonal Frequency Division Multiplexing) 변조방식을 사용하여 54 Mbps속도로 전송하기 때문에 기존의 802.11b MAC (Medium Access Control) 전송방식과 비교하여 통화시간을 만족시키는 것이 어렵다. 본 논문에서는 802.11g 규격을 적용한 단말기에서 통화중 Power Save 방법으로 Holdover Time을 처음으로 제안하므로 통화시간을 만족시킨다. 다만, 통화 단말기 수 증가에 따른 네트워크 혼잡으로 경합 창 (contention window)이 많이 발생하여, Back-off 수 증가로 인한 통화품질(QoS)의 문제가 발생하지만, QoS 해결 방안으로 다운 링크 시 802.11 G.711 Sequence Number를 단말기 MAC 단에서 분석하여 손실율에 따른 Holdover Time을 가변 하는 방법을 제안하므로 이 문제를 해결한다. 802.11b/g 소비전류 분석과 통화 단말기 증가에 따른 네트워크 혼잡에 의한 MAC 파라미터 성능을 분석하며, VQT장비와AiroPeek를 이용하여 실제적인 데이터를 분석한다.

• 한국생활과학회지
• /
• 제19권1호
• /
• pp.191-201
• /
• 2010

This study attempted to examine the application of retrograded starch (RS3) isolated from rice flour into Madeleine which is easy to make, supply enough energy and micro nutrients with adequate drinks, and prevent an adult disease. This could be a popular food to anyone regardless of age and gender who avoid rice and become high value-added, processed rice foods. For this, control Madeleine was made from wheat flour and an experimental one was made from 5 or 10% rice RS3 addition as well as wheat flour. Four different types of rice were produced from Premium Ho-Pyong Rice, that is, dry milled rice flour(RFD), soaked for 8 hours and milled, followed by air-dried rice flour(RFW), rice starch(RST), and retrograded rice starch or enzyme-resistant starch(RS3). The results found were as follows: Proximate compositions were decreased with soaking to make RFW, RST and RS3, compared to RFD. RS3 had the highest L, +a and ${\Delta}E$ with the lowest +b, changing it to a dark color, explaining the need for heat control during processing. At $80^{\circ}C$, the swelling power was shown in the order of RST>RFW>RFD>RS3 and the solubility of RS3 was the highest. There were significant differences in viscosities of peak, trough, cold, breakdown and total setback of all rice samples using RVA (p<0.001). Due to the pH of RS3, the Madeleine batter became acidic (p<.01) and expanded, resulting in more air cells and open texture. With an increasing RS3 level in Madeleine, several textural attributes among 'fresh' and 'stored at room temperature' Madeleine samples were significantly different by using Texture Analyzer. While the addition of RS3 in Madeleine did not significantly affect the sensory evaluation, indicating RS3 isolated from rice as a beneficial ingredient for processed rice products.

• 전기학회논문지
• /
• 제66권9호
• /
• pp.1309-1316
• /
• 2017

As penetration level of Distributed Generations (DGs) on weak distribution networks gets higher, voltage rise problem can often occur due to reverse power which is not expected in conventional distribution networks. It, however, cannot be effectively solved by using conventional voltage regulating devices such as On-Load Tap Changers (OLTCs), Step Voltage Regulators (SVRs) because those do not consider the presence of DGs when determining relevant setting parameter for voltage regulation. This paper presents a scheme for voltage regulation using coordinated control between OLTC and DGs which can actively participate in the regulation. The scheme decides which device should be operated first based on the characteristics of regulating devices, in order to prevent unnecessary operation of output changes of DG and excessive tap changing operation of OLTC. Computer simulations considering daily irradiation of PV and load curve are performed by using MATLAB Simulink and performance comparison between the presented scheme and conventional ones is also made. It can be concluded from simulation results that the scheme presented is very effective to regulate voltages in distribution networks with multiple DGs.

• 전기학회논문지
• /
• 제67권2호
• /
• pp.233-238
• /
• 2018

This paper proposes a seamless MPPT operation mode transfer method of photovoltaic system. The photovoltaic system consists of a DC-DC boost converter, a DC-Link, and a 3-level neutral point clamp (NPC) type inverter. The PV voltage fluctuates due to the output characteristics of the solar pane1 depending on the irradiation amount and the temperature. The photovoltaic system requires seamless MPPT mode transfer method that the discontinuity does not occur in order to supply the stable power to system without affecting the fluctuation of the PV voltage. MPPT operation is divided into two modes by the voltage reference. Under the condition that the PV voltage is below 650V, the DC-DC boost converter performs MPPT through duty control based on perturb & observe (P&O) method, and the inverter conducts DC-link voltage and grid current controls in synchronous reference frame. On the other hand, when the PV voltage exceeds above 650V, inverter performs MPPT in accordance with the variation of DC-link voltage control while the converter stops operating. Two MPPT operation modes is smoothly transferred through the proposed method that DC-link voltage or grid current commands are appropriately adjusted from the certain criteria. The feasibility of the MPPT operation mode transfer method is verified using a 10kW solar photovoltaic system, experimental results have good performances that the fluctuation of PV current is reduced to 100%.

• Ocean and Polar Research
• /
• 제35권1호
• /
• pp.15-26
• /
• 2013

The toxic, Harmful Algal Blooms (HABs) caused by the Cochlodinium polykrikoides have a serious impact on the coastal waters of Korea. In this study, the acoustic detection system was developed for rapid HABs detection, based on the acoustic backscattering properties of the C. polykrikoides. The developed system was mainly composed of a pulser-receiver board, a signal processor board, a control board, a network board, a power board, ultrasonic sensors (3.5 and 5.0 MHz), an environmental sensor, GPS, and a land-based control unit. To evaluate the performance of the system, a trail was done at a laboratory, and two in situ trials were conducted: (1) when there was no red tide, and (2) when there was red tide. In the laboratory evaluation, the system performed well in accordance with the number of C. polykrikoides in the received level. Second, under the condition when there was no red tide in the field, there was a good correlation between the acoustic data and sampling data. Finally, under the condition when there was red tide in the field, the system successfully worked at various densities in accordance with the number of C. polykrikoides, and the results corresponded with the sampling data and monitoring result of NFRDI (National Fisheries Research & Development Institute). From the laboratory and field evaluations, the developed acoustic detection system for early detecting HABs has demonstrated that it could be a significant system to monitor the occurrence of HABs in coastal regions.

• Nutrition Research and Practice
• /
• 제11권1호
• /
• pp.25-32
• /
• 2017

BACKGROUND/OBJECTIVES: Stress-induced cognitive impairment is related to the suppression of hippocampal neurogenesis that results from an increase of oxidative stress. Therefore, the aim of this study was to investigate the effects of administration of a blueberry drink, having a high antioxidant power, on the cognitive performance of adult rats exposed to chronic mild stress. MATERIALS/METHODS: Twelve-week-old male Sprague-Dawley rats (n = 48) were randomly divided into four groups: control (CO), stress (ST), control + 5% blueberry drink (CO + B), and stress + 5% blueberry drink (ST + B). After eight weeks, the cognitive performance was assessed using a multiple T-maze water test. Levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and ascorbic acid were measured in the brain, and catecholamine concentrations were measured in plasma. RESULTS: The brain weights of the rats from the ST and ST + B groups were significantly lower than those of the rats from the CO and CO + B groups. The cognitive performance of the ST group was impaired when compared to that of the CO group. This impairment was significantly improved by the blueberry drink supplementation (P < 0.05). The brain SOD and CAT concentrations were not influenced by the stress or by the blueberry drink. However, the brain levels of GPx and ascorbic acid were significantly lower in the ST group than those in the CO group and were increased by the blueberry drink supplementation. The plasma catecholamine concentrations were affected by chronic mild stress and by the blueberry drink. The plasma norepinephrine and dopamine concentrations were decreased by the chronic stress and improved by the blueberry drink supplementation. The plasma epinephrine level was only influenced by the stress. CONCLUSION: These findings suggest that the blueberry drink may protect against the cognitive impairment induced by chronic mild stress.