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        검색결과 2,981

        1.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study sought ways to connect urban above ground roads and underground roads to utilize urban space more efficiently in the development of underground roads, which are currently under development in order to alleviate problems caused by oversaturated above-ground roads. A simulation analysis was performed to develop an operation strategy that connects above-ground and underground roads to prevent congestion in above-ground areas such as entrances and exits from transferring to underground roads as well as to present its effectiveness. METHODS : Traffic efficiency analysis according to the operation strategy of above ground and underground roads was conducted using VISSIM, a microscopic traffic simulation software. The functions implemented in VISSIM were collected to set effectiveness analysis indicators for each underground road operation strategy. The Shinwol-Yeoui Underground Road was selected as the spatial scope of this study, and a surrounding road network was constructed. In addition, full-scale simulation analysis preparations were completed by performing network calibration based on the actual traffic attribute data of underground and surrounding surface roads within the construction scope. Accordingly, a traffic efficiency evaluation analysis was conducted based on the underground road operation strategy. CONCLUSIONS : Information on the increase in traffic volume within the Shinwol-Yeoui underpass was collected every 15 min. The analysis was divided into an analysis of the traffic situation within the underpass through demand control when the service level reached level D and an analysis of when demand control was not performed. It was found that demand control was necessary for the Shinwol-Yeoui Underpass when the internal traffic volume reached 2,500 vehicles/h. In addition, to analyze the spread of traffic and congestion owing to the weaving phenomenon caused by lane changes in the underpass, an analysis was conducted to observe the traffic improvement effect when full lane changes are possible for the Shinwol-Yeoui Underground Road, which currently has some lane-change-permitted sections. The analysis showed that both the maximum traffic volume and average travel speed showed better results when lane changes were allowed, and the communication situation at Yeoui JCT was found optimal.
        5,100원
        2.
        2024.04 구독 인증기관·개인회원 무료
        해양 부유식 구조물의 계류시설에 대한 연구는 다양한 계류 시스템의 개발과 그 효율성에 대해 지 속적으로 연구되어 왔다. 계류 시스템은 구조물의 안전성, 내구성, 그리고 환경적인 책임을 모두 고려 해야하는 복합적인 설계 요소이다. 기존 계류바익은 해저지반의 특성에 크게 의존하며, 넓은 점유 면 적으로 인해 해양환경과 활동에 부정적인 영향을 줄 수 있다. 이러한 기존 계류시스템의 한계와 문제 점에 대응하기 위해, 본 연구에서는 새로운 계류시스템을 제안하고자 한다. 제안된 계류시스템은 계류 선이 해저지반에 고정되지 않고 중력식 기초 구조물을 거쳐 중간부력재에 연결된다. 중간 부력재는 상 시 과잉 부력상태로 상향력이 작용하며, 이로인해 계류선에 초기장력이 유도되며 전체 시스템에 강성 을 도입한다. 전체적으로 Semi-taut과 유사한 방식으로 계류 장력 변화에 따른 상단 플랫폼의 운동 제어와, 중간 부력재와의 상호연계 거동효과로 추가적인 동적 응답 저감이 기대된다. 본 연구에서는 제안된 신형식 계류시스템의 역학적 거동특성을 수치해석적으로 구현하고 파랑에 대한 Catenary system 대비 운동 저감 성능을 검증하였다.
        3.
        2024.03 KCI 등재 구독 인증기관·개인회원 무료
        시설 고추 주요 해충인 꽃노랑총채벌레(Frankliniella occidentalis)의 방제를 위해 유기농업자재들의 단독 처리 및 종합 투입시 방제 효과를 검정 하였다. 황색끈끈이롤트랩은 지제부에 설치하고, 포식성 천적(Hypoaspis miles)은 지제부에 접종하며, 식물추출물(커스터드애플시드 오일 50% + 계 피 추출물 10%)은 경엽살포하는 방식으로써 각각의 단독 처리시 방제 효과는 45.3, 36.6, 50.2%였다. 한편, 3종의 유기농업자재들을 종합 투입했을 경우 고추 수확기 방제 효과가 무처리 대비 62.4~80.9%로 유지되어, 시설 고추 꽃노랑총채벌레 친환경 방제용으로 활용이 가능할 것으로 생각된다.
        4.
        2024.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to improve the stack effect of the staircase and the failure to take into account the opening of the outside door of the staircase, which are the disadvantages of the existing smoke control only vestibule. As a result of the study, the new vestibule and the staircase simultaneous smoke control are equipped with an exhaust flap damper with an effective opening area of about 0.25 m² in the upper part of the staircase, and a ventilator-type air supply fan of about 5 m³/s in the lower part, and take measures to prevent overpressure in the staircase. If you use the new simultaneous smoke control method of the vestibule and staircase, you can achieve the following effects. First, it is possible to open the external entrance door. Second, it can reduce the stack effect. Third, the staircase door closes automatically without fail. And a new method of preventing overpressure was proposed for the vestibule.
        4,000원
        5.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study develops a model that can estimate travel speed of each movement flow using deep-learning-based probe vehicles at urban intersections. METHODS : Current technologies cannot determine average travel speeds for all vehicles passing through a specific real-world area under obseravation. A virtual simulation environment was established to collect information on all vehicles. A model estimate turning speeds was developed by deep learning using probe vehicles sampled during information processing time. The speed estimation model was divided into straight and left-turn models, developed as fully-offset, non-offset, and integrated models. RESULTS : For fully-offset models, speed estimation for both straight and left-turn models achieved MAPE within 10%. For non-offset models, straight models using data drawn from four or more probe vehicles achieved a MAPE of less than 15%. The MAPE for left turns was approximately 20%. CONCLUSIONS : Using probe-vehicle data(PVD), a deep learning model was developed to estimate speeds each movement flow. This, confirmed the viability of real-time signal control information processing using a small number of probe vehicles.
        4,000원
        6.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study aims to propose drone-command standard operating procedure (SOP) guidelines and Analyze their potential application to increase the use and utility of drones in urban disaster situations. Although the effectiveness and efficiency of obtaining disaster-situation information through drones have been verified by previous studies and practical experience, a survey of actual drone usability indicated a utilization rate of only approximately 4.13%. METHODS : To provide guidance for improving drone command SOPs, prior research and relevant literature were reviewed to identify commonalities between disaster-response command and control and drone use. A sample of 73 active-duty firefighters, including incident commanders (ICs) and drone pilots, were surveyed and interviewed. The data were analyzed and categorized to establish the reasons why drones are not actively used in urban disaster-response procedures. RESULTS : The primary reasons identified for not actively utilizing drones in urban disaster areas were the lack of a drone command and control system and the lack of clear criteria for when to use drones in disaster situations. In addition, many problems were found in drone-operation procedures, including emergency flight approval, securing takeoff and landing sites, and accident burden due to urban flight obstacles. To address the issues identified, standards were proposed for the type, size, and scope of urban disasters requiring drone response; for accident-prevention on basic missions and through flight safety procedures; and for installing a video transmission and reception system to easily share drone video information with ICs. CONCLUSIONS : Application of the drone-command SOP guidelines to actual urban disaster situations by disaster type will help to improve the efficiency of information acquisition and flight safety. This is expected to enable increased drone utilization. In future, extension of the research reported in this paper beyond the Seoul metropolitan area via additional follow-up studies has the potential to establish applicability of the proposed SOP guidelines to a wide variety of environments and organizational characteristics.
        4,000원
        7.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Chronic back pain not only causes physical discomfort and decreased functionality but also affects emotional well-being, resulting in feelings of anxiety, depression, and other psychological issues. Studies have indicated that cognitive functional therapy and motor control exercises can alleviate chronic low back pain and associated psychological issues. Objectives: To investigated the effect of chronic low back pain on the cognitive functional therapy (CFT) and motor control exercises (MCE). Design: Quaxi-experimental study. Methods: Forty patients with chronic low back pain were randomly assigned and divided into 20 cognitive functional therapy group with motor control exercises group (CFTMG) and 20 patients in motor control exercises group (MCEG). After applying CFT with motor control exercises and motor control exercises for 8 weeks, changes in numeric pain rating scale (NPRS), Oswestry disability index (ODI) and Fear-avoidance beliefs questionnaire (FABQ) were observed. Results: In the CFTMG, statistically significant changes were observed in NPRS, ODI, and FABQ before and after the intervention. In the MCEG, statistically significant changes were observed in VAS and ODI before and after the intervention. Conclusion: The application of CFTM and MCE in patients suffering from chronic low back pain has demonstrated effectiveness in alleviating pain, enhancing back function, and reducing kinesiophobia associated with the condition.
        4,000원
        8.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A thermochemical conversion method known as hydrothermal carbonization (HTC) is appealing, because it may convert wet biomass directly into energy and chemicals without the need for pre-drying. The hydrochar solid product’s capacity to prepare precursors of activated carbon has attracted attention. HTC has been utilized to solve practical issues and produce desired carbonaceous products on a variety of generated wastes, including municipal solid waste, algae, and sludge in addition to the typically lignocellulose biomass used as sustainable feedstock. This study aims to assess the in-depth description of hydrothermal carbonization, highlighting the most recent findings with regard to the technological mechanisms and practical advantages. The process parameters, which include temperature, water content, pH, and retention time, determine the characteristics of the final products. The right setting of parameters is crucial, since it significantly affects the characteristics of hydrothermal products and opens up a range of opportunities for their use in multiple sectors. Findings reveal that the type of precursor, retention time, and temperature at which the reaction is processed were discovered to be the main determinants of the HTC process. Lower solid products are produced at higher temperatures; the carbon concentration rises, while the hydrogen and oxygen content declines. Current knowledge gaps, fresh views, and associated recommendations were offered to fully use the HTC technique's enormous potential and to provide hydrochar with additional useful applications in the future.
        6,300원
        9.
        2023.12 KCI 등재 구독 인증기관·개인회원 무료
        스마트팜형 시설 딸기에 예찰 없이 작물 정식 초기에 천적을 먼저 적용하는 생태공학적 Natural Enemy in First (NEF) 기법이 총채벌레류 와 진딧물류의 밀도에 미치는 영향을 확인하였다. 대조구는 약제를 처리하여 비교하였다. NEF 처리구에서 총채벌레류와 진딧물류의 천적과 서식 처로 참멋애꽃노린재와 Portulaca sp.를 적용하여 작기 종료시점까지 해충의 밀도를 대조구와 유사하게 효과적으로 관리할 수 있었다.
        10.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        제충국(Tanacetum cineariaiaefolium), 데리스(Derris elliptica), 고삼(Sophora flavescens) 추출물은 다양한 해충을 방제하는데 사용되고 있다. 하지만, 국내에서 판매되고 있는 식물추춞물 자재는 유효성분의 표기가 없고, 살충농도와 살충시간에 대한 자료가 전무한 상황이다. 본 연구에서는 상 용화된 주요 식물추출물의 살충유효성분의 농도를 결정하고 복숭아혹진딧물에 대해 살충농도와 살충시간을 측정하였다. 식물추출물의 살충활성성분 인 pyrethrins, rotenone, matrine과 oxymatrine의 농도는 액체 크로마토그래피에서 표준물질을 활용하여 질량분석을 통해 측정하였다. 식물추출 물을 농도별로 희석하여 복숭아혹진딧물에 살포하여 살충력을 측정하였다. 표준화합물과 비교한 후 질량분석 및 결정했습니다. Myzus persicae에 대 한 lethal concentation과 lethal time을 조사했다. 살포 후 48시간 후 치사 농도(LC50)는 pyrethrins (20.4 ppm), roteone (34.1 ppm), matrine (29.6 ppm)였고, 100 ppm 살포한 LT50은 pyrethrins (13.4시간), rotenone (15.1시간), matrine (14.4시간)로 측정되었다. Kaplan-Meier 생존분 석 결과, 100 ppm에서 세 가지 식물 추출물의 LT50은 대조구인 화학 살충제인 Sulfoxaflor를 살포 처리구보다 유의하게 빨랐습니다. 본 결과는 복숭 아혹진딧물 방제를 위해 식물추출물의 제형화에 단일 또는 혼합 제제를 개발하는데 기준 살충농도와 살충시간을 제고하는데 의미가 있다.
        4,000원
        11.
        2023.12 구독 인증기관 무료, 개인회원 유료
        This study explores the course tracking control problem of unmanned surface vessels (USVs) under the influence of actuator faults and internal and external uncertainties. In the control strategy desig n, we first model the unknown dynamics and use adaptive technology to construct an online appro ximator to compensate for the unknown dynamics of the system. Under the framework of adaptive backstepping, a robust adaptive course tracking control scheme is constructed. This control strategy does not require any prior knowledge of the model in advance. The stability analysis of the theoret ical mathematical derivation of the control strategy was conducted based on Lyapunov stability theo ry. Finally, the effectiveness of the control strategy proposed in this paper was verified through sim ulation.
        4,000원
        12.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study developed an IoT-based agricultural well control system and demonstrated it through a control system in the current state of domestic open-field smart farms where systematic management is insufficient due to the difficulty of collecting accurate data such as agricultural water intake and usage. As a result, it was possible to derive the optimal control system test results according to the watering conditions for each schedule by conducting automatic control focusing on periods when there is no precipitation. This means that irrigation can be carried out smoothly during the time when irrigation is needed to improve crop quality and secure farm income, and as a result, it is possible to systematically manage and operate among demonstration farms connected to irrigation, resulting in a shortage of agricultural water and a resolution of supply imbalances.
        4,000원
        13.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        For motor controller designers, building a simulation environment is not a difficult process. After verifying the controller by simulation, it is common to select 20kHz for the current control loop, 1kHz for the speed loop, and 100Hz for the position loop when implementing the actual HW embedded system. This is because maximized cycles (20kHz) for each control loop are unnecessary in control theory and are a waste of cost and HW resources. However, in a simulation environment, each loop will often have the same control cycle (20kHz maximum). This is because we think it is unnecessary to reflect this part in the simulation. In this paper, it is shown that the difference in the sampling time of each control loop makes a big difference in the simulation result, and as a solution, it is proposed to apply LPF to the position loop output stage. In the process, the reasons for the differences were analyzed, and the effect of LPF, the reason for application, and the feasibility of implementation were proved by actual software coding.
        4,000원
        14.
        2023.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The theoretical capacity of silicon-based anode materials is more than 10 times higher than the capacity of graphite, so silicon can be used as an alternative to graphite anode materials. However, silicon has a much higher contraction and expansion rate due to lithiation of the anode material during the charge and discharge processes, compared to graphite anode materials, resulting in the pulverization of silicon particles during repeated charge and discharge. To compensate for the above issues, there is a growing interest in SiOx materials with a silica or carbon coating to minimize the expansion of the silicon. In this study, spherical silica (SiO2) was synthesized using TEOS as a starting material for the fabrication of such SiOx through heating in a reduction atmosphere. SiOx powder was produced by adding PVA as a carbon source and inducing the reduction of silica by the carbothermal reduction method. The ratio of TEOS to distilled water, the stirring time, and the amount of PVA added were adjusted to induce size and morphology, resulting in uniform nanosized spherical silica particles. For the reduction of the spherical monodisperse silica particles, a nitrogen gas atmosphere mixed with 5 % hydrogen was applied, and oxygen atoms in the silica were selectively removed by the carbothermal reduction method. The produced SiOx powder was characterized by FE-SEM to examine the morphology and size changes of the particles, and XPS and FT-IR were used to examine the x value (O/Si ratio) of the synthesized SiOx.
        4,000원
        15.
        2023.12 KCI 등재 구독 인증기관·개인회원 무료
        본 연구에서는 운전 시뮬레이션을 사용하여 자율주행 환경을 구현한 후 3-수준 자율주행 조건에서 자율주행 차량 (automated vehicle: AV)으로부터 운전자에게 전달되는 제어권 인수 요구(takeover request: TOR) 정보의 양상(시각, 청각 및 시각+청각) 및 도로 형태(직선도로와 곡선도로)에 따라 운전자의 제어권 인수 시간(takeover time: TOT) 및 정신적 작업부하(제어권 인수 이후에 운전자들이 경험한 주관적 작업부하와 심장박동수에서의 변화)가 어떻게 차별 화되는지 분석하였다. 본 연구의 결과를 요약하면 다음과 같다. 먼저, AV로부터 TOR이 제시된 이후 실험참가자들 이 보인 TOT에 대한 분석 결과, TOR 정보양상의 측면에서는 시각 정보가 가장 빠른 TOT를 이끌어 낸 반면 청각 정보 조건에서 가장 느렸고, 도로 형태 측면에서는 직선도로 조건에 비해 곡선도로 조건에서의 TOT가 유의하게 더 느렸으며, 특히 청각 정보 조건에서 도로 형태에 따른 TOT에서의 차이가 가장 컸다. 둘째, 정신적 작업부하에 대한 분석 결과, TOR 정보가 시각 혹은 시각+청각적으로 제시된 조건에 비해 청각적으로 제시된 조건에서 주관적 작업부 하 측정치와 심장박동수 변화 크기 모두 전반적으로 더 낮았고 특히, 심장박동수 변화의 경우 이러한 경향은 곡선도 로 조건에서만 관찰되었다. 이러한 결과는 TOR 정보의 양상과 도로 형태에 따라 운전자의 TOT와 정신적 작업부하 수준이 달라질 수 있고, 특히 TOT가 빠를수록 정신적 작업부하 수준은 상대적으로 더 높아질 수 있음을 시사한다.
        16.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Highly safe lithium-ion batteries (LIBs) are required for large-scale applications such as electrical vehicles and energy storage systems. A highly stable cathode is essential for the development of safe LIBs. LiFePO4 is one of the most stable cathodes because of its stable structure and strong bonding between P and O. However, it has a lower energy density than lithium transition metal oxides. To investigate the high energy density of phosphate materials, vanadium phosphates were investigated. Vanadium enables multiple redox reactions as well as high redox potentials. LiVPO4O has two redox reactions (V5+/V4+/V3+) but low electrochemical activity. In this study, LiVPO4O is doped with fluorine to improve its electrochemical activity and increase its operational redox potential. With increasing fluorine content in LiVPO4O1-xFx, the local vanadium structure changed as the vanadium oxidation state changed. In addition, the operating potential increased with increasing fluorine content. Thus, it was confirmed that fluorine doping leads to a strong inductive effect and high operating voltage, which helps improve the energy density of the cathode materials.
        4,000원
        17.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Southern root-knot nematode (SRKN, Meloidogyne incognita) is known to be responsible for annual economic losses of 38.2 million USD in cucumber cultivation in Korea. Nematicides are frequently used to manage SRKN in plastic greenhouses. A field experiment was conducted to assess the effect of a soil fumigant (dimethyl disulfide, DMDS) and a non-fumigant (fluopyram, FL) against SRKN during the winter fallow season in a greenhouse from October to December. Nematicidal efficacy was assessed at 43 days after treatment, and the root gall index was measured 4 months after transplanting cucumber seedlings. DMDS effectively reduced second-stage SRKN juvenile density with 91% control efficacy, while FL showed no control efficacy against SRKN. Root gall index values were significantly different (p=0.020) in DMDS treatment and controls at 1.0±0.00 and 4.3±0.58, respectively. This study showed that DMDS could be considered an effective nematicide for controlling SRKN in the fallow period in winter.
        4,000원
        18.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to analyze the effects of stand density on fire fuel (FF) changes in a Chamaecyparis obtusa forest. The study site was located in Mt. Munsu in Jeollabuk-do and consisted of a control, 30% thinning treatment (LT), and 50% thinning treatment (HT). Three-year-old seedlings were planted at a density of 3,000 trees ha-1 in 1976, and thinning was carried out in 2000. FF production was measured every 2 months by installing 3 circular litter traps 1.2 m above the ground. Litter bags containing 5 g of each leaf and branch were made and buried in the organic layer to investigate the FF decomposition rate. The decay constant was calculated after 18 months. FF accumulation was measured by collecting dry-weight organic matter from each plot using a square frame (0.09 m2) in September 2018. The FF production in LT and HT was significantly lower than that of the control (P<0.001). The leaf decay constant for HT was significantly lower than that of the control (P<0.05). The FF accumulation in HT was significantly lower than that of the control (P<0.01), but LT was not significantly different from the control. The results of this study showed that thinning decreased FF production.
        4,000원
        19.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        총채벌레는 우리나라에 60여 종이 알려져 있으며 다양한 시설작물에서 직접적인 섭식 피해 이외에 토마토반점위조바이러스(TSWV)를 매 개하는 간접적인 피해도 유발한다. 그동안 총채벌레 방제는 살충제에 의존해 왔는데, 이는 농업환경에 많은 부작용을 유발하고 해충의 저항성을 유발시켜 더욱 방제를 어렵게 하고 있다. 이러한 문제를 해결할 수 있는 대안으로 내성 회피를 위한 물질을 탐색하였다. 실내검정으로 약용작물 67종의 추출물을 꽃노랑총채벌레 성충에 처리하여 가장 효과가 우수한 목단피를 선발하였다. 목단피 추출물을 처리 후 1일차에 100%의 살충효 과를 보였다. 또한, 목화진딧물은 3일차 83%, 복숭아혹진딧물 3일차 97%, 점박이응애 1일차 100%의 살충효과를 보였다. 고추 포트 검정에서 꽃노랑총채벌레 방제가는 1일차 77.6%, 2일차 40%의 효과가 나타났다. 현재 추가적으로 효과를 증대시킬 수 있는 물질을 탐색하고 있으며, 총 채벌레 방제에 본 추출물을 활용한다면 효과적일 것으로 기대된다.
        4,000원
        20.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Considering the characteristics of aldehydes among volatile organic compounds, a combined process was established by linking an absorbent and a photocatalytic reactor. Experiments to find the optimal operating conditions of the combined process showed that as the amount of photocatalyst coating increases, the wavelength of the ultraviolet lamp used becomes shorter, the photodegradation rate becomes faster, and the removal efficiency increases. It was also demonstrated that by controlling the relative humidity during the connection process of the combined process, the re-evaporation phenomenon at the front end (absorption area) of the hybrid process can be improved and the removal efficiency at the back end (photocatalytic reaction area) can be significantly enhanced. This confirmed the need for a combined process that complements the advantages and disadvantages of each process.
        4,000원
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