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        검색결과 3,049

        2.
        2025.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we aimed to understand the effects of pest control on forest ecosystems by examining the populations of beetles, a bioindicator species, in pine wilt disease-affected areas. Density and diversity of beetles at the pest control (sites 1 and 2) and control (site 3) sites were compared. Site 1 contained 247 individuals of 11 species from 5 families, site 2 contained 461 individuals of 19 species from 9 families, and control site 3 contained 511 individuals of 19 species from 9 families. The following main species were collected from each site: 34 pine jewel beetles(Chalcophora japonica) in June, 23 red flat bark beetles(Synuchus cycloderus) in August, and 42 red flat bark beetles in September from site 1, 46 pine jewel beetles in June, 36 elegant beetles(Carabus jankowskii) in August, and 21 elegant beetles in September from site 2, and 31 red ground beetles(Coptolabrus smaragdinus) in June, 56 two-spotted dust beetles(Planetes puncticeps) in August, and 30 two-spotted dust beetles in September from site 3. Furthermore, diversity, evenness, and dominance indices were analyzed for all beetles collected from the pest control and control sites. Site 1 exhibited a diversity index of 0.706, evenness index of 0.711, and dominance index of 0.161. Site 2 exhibited a diversity index of 1.115, evenness index of 0.872, and dominance index of 0.097. Site 3 exhibited a diversity index of 1.101, evenness index of 0.861, and dominance index of 0.102. Similarity index was 47.4% between sites 1 and 2, 33.3% between sites 1 and 3, and 40.0% between sites 2 and 3.
        4,200원
        3.
        2025.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we propose an adaptive traffic control method that utilizes predictions of near-future traffic arrivals at a signalized intersection based on real-time data collected at an upstream intersection to design acyclic traffic signal timing accordingly. The proposed adaptive control method utilizes a deep learning model developed in this study to predict future traffic arrivals at downstream intersections 24 s ahead based on upstream intersection data at 4 s decision intervals. Using the predicted arrival traffic volume, signal timings were designed to minimize delays. A rolling-horizon approach was employed to correct the prediction errors during this process. The performance of the proposed traffic signal control method was validated by comparing it with the traditional time-of-day (TOD) traffic signal operation method over a 24 h period. The results of comparative validation tests conducted through simulations in a virtual environment indicate that the proposed adaptive traffic control system operates efficiently to minimize average control delays. During the morning peak period, a reduction time of 43.19 s per vehicle (57.02%) was observed, whereas the afternoon peak period exhibited a reduction of 37.91 s per vehicle (48.35%). Additionally, data analysis revealed that the optimal phase length suggested by the pre-timed method, which assumes uniform vehicle arrivals, is statistically identical at a 95% confidence level to the average phase length of the adaptive traffic control system, which assumes random vehicle arrivals. This study confirms the necessity of adopting proactive real-time signal control systems that utilize a new traffic information collection method to respond to dynamic traffic conditions and move away from conventional TOD signal operation, which primarily focuses on peak commuting hours. Additionally, it confirms the need for a fundamental shift in the underlying philosophy traditionally used in traffic signal design
        4,300원
        4.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        정원과 대조구 간 열 환경 요소의 차이와 정원 구성 요소 간 열 환경과 열 스트레스 지수의 차이에 대한 결과는 다음과 같다. 정원과 대조구 간 열 환경 요소의 시계열 변화에서 대기 온도의 차이는 0.8°C에서 2.4°C까지 나타났고, 흑구 온도는 4.4°C까 지 나타났으며, WBGT는 1.6°C 차이가 나타났다. 대조구에 비 해 정원의 열 환경이 모든 온도에서 낮게 나타난 것이다. 특히, 대조구와 정원의 온도 증가 폭을 비교해 보면, 정원에서 모두 온도의 완만한 증가 폭을 확인할 수 있었다. 정원이 급격한 온도 차이는 만들어낼 수 없으나, 소규모 녹지를 활용한 지속적인 온도 조절에 효과를 보일 수 있겠다. 이용객이 느끼는 열 스트레 스 지수도 정원에서 낮게 나타나 정원이 열 쾌적감 증진 역할을 할 수 있다고 판단된다. 정원 구성 요소에 따른 열 환경 변화를 비교하였을 때, 목재 소재의 시설물이 표면 온도가 높았고, 녹지 에 의해서 생긴 그늘이 온도 차이를 줄일 수 있는 요소가 되었다. 실외 미기후를 대상으로, 정원 입지 환경 중에 하나인 건물에 의한 그늘과 녹지 그늘이 열 스트레스 지수인 UTCI에서 동일하 게 ‘moderate’ 수준을 나타냈다. 즉, 건물 그늘의 일사 차단 효과로 인해 열 쾌적감이 증진되는데, 건물이 없는 소규모 녹지 에서도 교목과 초지 식재로 열 쾌적감 증진에 효과를 높일 수 있다. 이와 같이 정원 구성 요소에 미기후 조절 효과에 관련이 있는 요소를 선정하였을 때, 건물→수목→주변 포장재→정원 포 장재→시설물의 순서로 정원 입지 선정과 구성 요소 선택에 활 용할 수 있는 가이드를 마련할 수 있을 것이다.
        4,200원
        5.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 국내 지진발생 빈도 및 규모가 증가하면서 원자력 발전소의 안전성 향상에 대한 요구가 높아지고 있다. 이에 국내 원 전 업계에서는 안전정지지진의 수준을 상승시키는 등 원자력 안전사고 대응능력을 향상시키기 위하여 노력하고 있다. 원자력 안전사고 에 대한 평가는 지진취약도 평가를 통해서 이루어질 수 있으며, 원자력기기의 정확한 내진성능평가를 위해서는 파괴한도실험이 필요하 다. 본 연구에서는 원전의 대표적인 안전기기 중 하나인 Motor Control Center에 대하여 초기 상태와 가속열화 상태에 대하여 파괴한도 실험을 수행하고 취약도를 분석하였다. 취약도 평가에 사용되는 요구응답스펙트럼은 설계용과 울진지역의 Uniform Hazard Spectrum을 이용하여 도출된 보수적인 요구응답스펙트럼이 사용되었다. 분석결과 MCC는 열화 상태에서 초기 상태에 비하여 내진성능이 미소하게 낮게 평가되었으며, 보다 정확한 내진성능평가를 위해서는 입력지진에 대한 추가적인 연구가 필요할 것으로 판단된다.
        4,000원
        6.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ceramic materials have become essential due to their high durability, chemical stability, and excellent thermal stability in various advanced industries such as aerospace, automotive, and semiconductor. However, high-performance ceramic materials face limitations in commercialization due to the high cost of raw materials and complex manufacturing processes. Aluminum borate (Al₁₈B₄O₃₃) has emerged as a promising alternative due to its superior mechanical strength and thermal stability, despite its simple manufacturing process and low production cost. In this study, we propose a method for producing Al₁₈B₄O₃₃ spherical powder with increased uniformity and high flowability by controlling the particle size of B₂O₃. The content ratio of the manufactured Al18B4O33 spherical powder was Al2O3: B2O3 = 87:13, and it exhibited a 17% reduction in the Hausner ratio (1.04) and a 29% decrease in the angle of repose (23.9°) compared to pre-milling conditions, demonstrating excellent flowability.
        4,000원
        7.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        생물학적 탈질반응에서 하폐수의 C/N비가 충분하지 않거나 유출수의 질소농도를 낮은 수준까지 처리하는 것을 목표로 할 경우에는 외부탄소원의 주입이 요구된다. 본 연구에서 연속회분식반응조의 질산화 반응특성을 잘 파악할 수 있고 무엇보다도 탈질반응의 대상물질인 질산염의 양을 추정할 수 있는 호흡률을 활용하여 탈질공정을 제어하고자 하였다. 호흡률을 측정하여 질산화에 의해 생성된 질산염을 추정할 수 있었으며, 추정치는 반응조내 질산염의 약 90% 정도에 해당되어 비교적 정확하였다. 추정한 질산염의 양에 상응하여 외부탄소원으로 초산염의 주입량을 조절하였으며, 운전결과 질산성 질소당 요구되는 COD는 4.25 mg COD/mg N이 적절하였다. 또한 초산염의 주입에 따라 미생물의 세포내에 유기물로 축적되고 이를 이용한 성장에서 호흡률의 변화가 나타나는 것을 파악할 수 있었다. 연구결과 연속회분식반응조에서 호흡률을 활용하여 초산염의 주입량을 조절함으로써 매우 엄격한 수준의 유출수 질소농도까지 효과적으로 처리할 수 있었다.
        4,800원
        8.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Indoor Air Quality Control Act aims to regulate indoor air quality (IAQ) to safeguard public health and promote a comfortable living environment. This law encompasses multi-use facilities, newly constructed residential complexes, and public transportation vehicles. The law also involves mandating air quality standards, conducting periodic measurements, and transparent public reporting of results. Over time, the Indoor Air Quality Control Act has expanded to enforce stricter controls on building materials and enhance radon mitigation measures. In doing so, it embodies the principles of the Environmental Policy Basic Act and is supported by other laws, policies, and systems related to air quality management. In line with these efforts, local governments have been implementing IAQ initiatives tailored to regional needs, including consulting services and financial support. However, challenges persist in harmonizing management across diverse facilities due to overlapping responsibilities among laws and government bodies. Future recommendations emphasize integrated strategies and enhanced inter-agency coordination to address these gaps effectively, ensuring healthier indoor environments for all stakeholders.
        4,500원
        9.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Due to the onset of urbanization worldwide, there is an increasing demand for improving the quality of the urban environment. Odor in wastewater collection systems (WCSs) can interfere with the comfortable and safe living conditions of citizens. Additionally, it can cause economic losses, such as the corrosion of wastewater collection facilities. In this paper, the mechanism of odor generation in WCSs was summarized, and the odor concentrations and sulfide generation rates measured in domestic and foreign WCSs were comprehensively analyzed to review the characteristics of odor emission in WCSs. The complex odor intensity (dilution-tothreshold value) measured in combined domestic sewers ranged from 10 to 10,000, with a median of 100. The odorous compound with the highest contribution to complex odor intensity was hydrogen sulfide, which was the odor most frequently detected at the highest concentrations in most WCSs (its median and mean concentrations were 378.0 ppb and 3,771.2 ppb, respectively). The odor emission properties in the WCSs in Australia and Finland were similar to those of South Korea, with the median and mean concentrations of hydrogen sulfide being 1,927.5 ppb and 12,306.1 ppb, respectively. The sulfide generation rates measured in domestic and foreign WCSs ranged from 0.003 to 0.220 g m–2 h–1. In addition, the key factors affecting sulfide generation were sulfate and organic matter concentrations, pH, temperature, flow rate (retention time), dissolved oxygen concentration, and electron acceptor concentrations other than sulfate. To control odor in WCSs, various methods have been proposed to improve their anaerobic environment. These include sucking outside air into the WCSs and improving their hydraulic conditions, such as changing the slope of sewer pipes to minimize sediment deposition. Additionally, periodically removing sediments, which contain a significant amount of organic matters and sulfate-reducing bacteria, is also a useful method for controlling odor in WCSs. Since the odor compounds that contribute the highest odor intensity–and are the most frequently detected–are sulfur-containing odors such as hydrogen sulfide, the control of sulfides is crucial for controlling odor in WCSs. There are chemical control methods for the mitigation of sulfide in WCSs, including air (oxygen) injection and introducing various chemicals, such as alkalis, nitrates, iron salts, and biocides. However, most of the results of odor control using these methods were from laboratory-scale studies. Therefore, additional field-scale experiments should be conducted in WCSs to evaluate the actual effectiveness of various odor control methods. Through these field studies, the optimal conditions for each method to control odor in WCSs can be derived, and the efficiency and economic feasibility of each method can be verified.
        5,400원
        10.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A study was conducted to evaluate the proper particle cleaned air changes per hour (PCH) in apartment buildings and school classrooms. The concept of PCH was newly introduced. The PCH can be expressed as the clean air delivery rate (CADR) per space volume. The PCH includes the filtering effect with air changes per hour (ACH). A method for calculating the proper PCH was theoretically proposed and experimentally verified. The proper PCH to effectively control ultrafine particles in apartments and school classrooms was found to be 4.0/h and 4.2/h, respectively. In general, air cleaners and mechanical ventilation devices are often used together in apartments and school classrooms. In such cases, it is important to consider the proper PCH of each device and control it for energy-efficient operation. In addition, in times of concern for infection such as COVID-19, it will be necessary to operate the PCH at 6.0/h or more to minimize the probability of infection.
        4,000원
        11.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study compares and analyzes the discharge status of smoke according to the method of installing a mobile blower in the event of a fire in an underground parking lot of an apartment using an evacuation simulation. An evacuation simulation was conducted on the situation in which the discharge of smoke in the event of a fire was discharged using a mobile blower to extinguish the smoke in the event of a fire by focusing on the part without smoke facilities in the underground parking lot. The results derived through experiments on the amount of smoke discharged using the natural exhaust method and the mobile blower in the underground parking lot are as follows. (1) In the event of a fire in an underground parking lot, the PPV (positive pressure ventilation) method, which has been mainly used in the field, should be used in a limited way. It can be an effective method if the exhaust port corresponding to the amount of the blower and the smoke exhaust is located nearby, or if the capacity of the apartment ventilation fan is designed to meet the 18CMH/㎡ of the National Fire Protection Association (NFPA) 88A or the 27CMH/㎡ standard standard for performance-oriented design evaluation and operation such as fire fighting facilities of the National Fire Protection Association (NFPA) 88A. (2) In the case of the additional mixing method (PPV+NPV) performed in the FDS experiment, smoke emissions increased by 5.1% compared to the NPV single method, and increased by 24.4% compared to the PPV single method.
        4,000원
        12.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aims to implement an integrated control system for a micro drill bit grinding machine to increase the processing stability and production efficiency of the equipment. The system consists of a WTGM mechanism, an environmental measurement sensor (RMU device), a control server, and a control client, and collects production statistics and alarm information in real time to enable central monitoring and statistical analysis. Through the control system, managers can check data and solve problems anytime and anywhere, thereby increasing the stability and efficiency of the production process. As a result of the experiment, it showed excellent performance in all evaluation items such as alarm occurrence time, notification time, and event operation time through temperature and humidity sensors, and contributed to productivity improvement through immediate response through e-mail and SNS notification. In conclusion, the implemented system optimizes the operating rate and inventory management of the equipment through real-time monitoring and yield analysis, and it is expected to improve system performance as it can be used as learning material for pattern analysis and deep learning algorithms in the future.
        4,000원
        13.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Purpose: This single-group pre-post experimental study aimed to develop and apply a simulation-based infection control education program for neonatal intensive care unit (NICU) nurses to verify its effectiveness and provide baseline educational materials to strengthen NICU nurses’ infection control competencies. Methods: The educational program was developed according to the five phases of analysis, design, development, implementation, and evaluation models, with scenarios based on the educational needs of NICU nurses. To verify the program’s effectiveness, a study was conducted on 28 NICU nurses of general and tertiary hospitals. NICU nurses’ infection control knowledge, performance confidence, critical thinking disposition, and satisfaction with the education were surveyed after applying the education program. Results: The simulation-based NICU infection control educational program was effective for NICU nurses’ infection control knowledge (t=−7.35, p < .001), performance confidence (t=−6.30, p < .001), and critical thinking disposition (t=−5.12, p < .001). Conclusions: The infection control educational program can contribute to infection prevention and patient safety by improving the NICU nurses' infection control competencies and be used as a baseline educational material for infection control education.
        4,800원
        15.
        2024.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this paper, we deal with the design of a model predictive control (MPC) for precise speed servo control of DC motor systems. The proposed controller is designed in the form of optimal control that calculates and outputs the optimized control input under constraints for each sampling. In particular, MPC designs the control inputs in advance for each sampling and predicts the outputs using them. Thus, it shows excellent control performance even in the case of disturbance or model uncertainty. The effectiveness of the proposed controller was demonstrated through computer simulations using MATLAB/Simulink and DC motor experimental system using real time controller. Moreover, the effectiveness of the proposed controller was confirmed by comparing its control performance with PID controller, which was tested under the same experimental condition as the MPC.
        4,000원
        18.
        2024.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Analyzing and diagnosing the causes of abnormal conditions through control logic processes at the plant site is critically important. When a process is halted, the steps for cause analysis and corrective action vary depending on the operator's experience and the specific characteristics of the process. Since it's often not feasible to keep the process stopped for an extended period, issues are sometimes resolved by forcibly restarting the PLC(Programmable Logic Controller). However, this can lead to the recurrence of the same error, which may negatively impact process operations. In particular, oil sands development is an uncharted area with anticipated environmental challenges. In this regard, an integrated system between control systems in the oil sands production plant was established to implement control logic, develop the HMI(Human-Machine Interface), and verify the user interface. This allowed for a better understanding of the equipment's operability.
        4,000원
        19.
        2024.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was performed to analyze dietary influences on the regulation of low-density lipoprotein cholesterol (LDL-C) in postmenopausal women using the 2019-2021 Korea National Health and Nutrition Examination Survey (KNHANES). A total of 1,724 women were classified into cardiovascular risk groups based on risk factors and differentiated into high LDLC and normal groups according to the target serum LDL-C levels. The risk group distribution was as follows: Very high-risk group (6%), high-risk group (49.4%), moderate-risk group (42.3%), and low-risk group (2.3%). The high LDL-C group demonstrated abdominal obesity and prediabetes, with their carbohydrate energy intake exceeding the Korean dietary guideline recommendations of 65%. Increased fat (OR 2.67, 95% CI; 1.19-6.02) and cholesterol (OR 2.43, 95% CI; 1.02- 5.77) intake correlated with higher LDL-C risk. The high LDL-C group showed elevated saturated fat and reduced polyunsaturated fat consumption (p for trend <0.001). Thus, to regulate the LDL cholesterol levels in postmenopausal women, they maintain an appropriate weight in addition to managing abdominal obesity and continuously monitoring blood sugar levels. Furthermore, it is important to limit the intake of high saturated fat meats and consume sufficient protein from sources such as beans, fish, and eggs, which contain healthy unsaturated fats.
        4,200원
        20.
        2024.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
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