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        검색결과 46

        1.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In recent automated manufacturing systems, compressed air-based pneumatic cylinders have been widely used for basic perpetration including picking up and moving a target object. They are relatively categorized as small machines, but many linear or rotary cylinders play an important role in discrete manufacturing systems. Therefore, sudden operation stop or interruption due to a fault occurrence in pneumatic cylinders leads to a decrease in repair costs and production and even threatens the safety of workers. In this regard, this study proposed a fault detection technique by developing a time-variant deep learning model from multivariate sensor data analysis for estimating a current health state as four levels. In addition, it aims to establish a real-time fault detection system that allows workers to immediately identify and manage the cylinder’s status in either an actual shop floor or a remote management situation. To validate and verify the performance of the proposed system, we collected multivariate sensor signals from a rotary cylinder and it was successful in detecting the health state of the pneumatic cylinder with four severity levels. Furthermore, the optimal sensor location and signal type were analyzed through statistical inferences.
        4,200원
        4.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The initial smoothness of concrete pavement surfaces must be secured to ensure better driving performance and user comfort. The roughness was measured after hardening the concrete pavement in Korea. When the initial roughness is poor, relatively large-scale repair works, such as milling or reconstruction must be performed. Hence, a method to measure the roughness of the concrete pavements in realtime during construction and immediately correct the abnormal roughness was developed in this study. METHODS : The profile of a concrete pavement section was measured at a construction site using sensors that were attached to the tinning equipment of the paver. The measured data included outliers and noise caused by the sensor and vibration of the paving equipment, respectively, which were further calibrated. Consequently, the calibrated data were input into the ProVAL program to calculate the roughness based on the international roughness index (IRI). Additionally, the profile of the section was re-measured using another method to verify the reliability of the calculated IRI. RESULTS : The profile data measured at the concrete pavement construction site were calibrated using methods, such as overlapped boxplot outlier removal and low-pass filtering. The outlier data from the global positioning system (GPS), which was installed to identify the construction distance, was also calibrated. The IRI was calculated using the ProVAL program by matching the measured profile and GPS data, and applying the moving average method. The calculated IRI was compared to that measured using another method, and the difference was within the tolerance. CONCLUSIONS : A method to measure the roughness of the concrete pavements in real time during construction was developed in this study. Hence, the performance of concrete pavements can be improved by enhancing the roughness of the pavement considerably using the aforementioned method.
        4,600원
        6.
        2022.05 구독 인증기관·개인회원 무료
        In order to enhance the transparency of nuclear power, the investigation of nuclear activities is important at the right time. And investigation of North Korea, one of safety measures for such a surveillance system seems essential in the near future. However, the inspection period is limited and the possibility of revisiting is unclear, so it seems easy to install and more reliable monitoring devices are needed. The seal is a security device for monitoring forgery and alteration in the IAEA easily but simple. Since the existing seal devices used by IAEA and KINAC can only be checked through onsite inspections whether it is damaged or not, there is a limit to immediate response in the event of an emergency such as the theft of nuclear materials and loss of Continuity of Knowledge. While the North Korea-U.S. talks and inter-Korean talks are slowly approaching the North Korea’s nuclear issue, it is judged that the inspection of North Korea’s nuclear weapons is not in the distant future. Accordingly, it is necessary to develop a customized seal device for managing and monitoring spent nuclear fuel that can be used for inspection of North Korea. The real-time active seal device consists of a seal equipped with a detection sensor, a translator, and a server, and the translator use wireless communication in consideration of ease of installation and management, respectively. The translator and server use wired communication for data sustainability. The seal device is designed to maintain continuity of knowledge (COK) through wireless communication in consideration of security even in the event of equipment damage, malfunction, and loss of power, while enabling location detection in case of theft or abnormality. Therefore, in this study, a technical investigation on remote data communication was conducted accordingly, and a data communication module for a small amount of broadband data communication was manufactured and applied. In addition, several tests were conducted to determine data integrity and location accuracy according to the communication range.
        7.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        수역 내 충돌 위험 식별은 항해의 안전을 위해 중요하다. 본 연구에서는 거리 요인을 기반으로 한 군집화 방법인 계층 클러스 터링을 포함하는 새로운 충돌 위험 평가 방법을 도입했으며, 주변의 선박이 많은 경우 실시간 데이터, 그룹 방법론 및 예비 평가를 사용하여 선박을 분류하고 충돌위험평가를 기반으로 평가하였다(HCAAP 처리라 부른다). 조우하는 선박들의 군집은 계층 프로그램에 의해 모아지고, 예비 평가와 결합되어 상대적으로 안전한 선박을 걸러내었다. 그런 다음, 각 군집 내에서 조우하는 선박 사이의 최근접점(DCPA) 및 최근접점까지의 도착시간(TCPA)까지의 시간을 계산하여 충돌위험지수(CRI)와의 관계를 비교하였다. 조우하는 선박들간의 군집에서 CRI와 DCPA 및 TCPA 수학적 관계는 음의 지수 함수로 구성되었다. 이러한 CRI로부터 운영자는 명시된 해역에서 항해하는 모든 선박의 안전성을 보다 쉽게 평가할 수 있으며, 프레임워크는 해상운송의 안전과 보안을 개선하고 인명 및 재산 손실을 줄일 수 있다. 본 연구에 서 제안된 프레임워크의 효과를 설명하기 위해 국내의 목포 연안 해역에서 실험 사례 연구를 수행하였다. 그 결과, 본 연구의 프레임워크가 각 군집 내에서 조우 선박 간의 충돌 위험 지수를 탐지하고 순위를 매기는 데 효과적이고 효율적이라는 것을 보여 주었으며, 추가연구를 위한 자동 위험 우선순위를 지정할 수 있게 해주었다.
        4,000원
        8.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, acoustic and viscosity data are collected in real time during the ball milling process and analyzed for correlation. After fast Fourier transformation (FFT) of the acoustic data, changes in the signals are observed as a function of the milling time. To analyze this quantitatively, the frequency band is divided into 1 kHz ranges to obtain an integral value. The integrated values in the 2–3 kHz range of the frequency band decrease linearly, confirming that they have a high correlation with changes in viscosity. The experiment is repeated four times to ensure the reproducibility of the data. The results of this study show that it is possible to estimate changes in slurry properties, such as viscosity and particle size, during the ball milling process using an acoustic signal.
        4,000원
        11.
        2019.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        As information technology advances, the penetration of smart devices connected to the Internet, such as smart phone and tablet PC, has rapidly expanded, and as sensor prices have fallen the Internet of Things has begun to be introduced in the industry. Today's industry is rapidly changing and evolving, requiring companies to respond to the new paradigm of business. In this situation, companies need to actively manage and maintain customer relationships in order to acquire loyal customers who bring them a high return. The purpose of this study is to suggest a method to manage customer relationship using real time IoT data including IoT product usage data, customer characteristics and transaction data. This study proposes a method of segmenting customers through RFM analysis and transition index analysis. In addition, a real-time monitoring through control charts is used to identify abnormalities in product use and suggest ways of differentiating marketing for each group. In the study, 44 samples were classified as 9 churn customers, 10 potential customers, and 25 active customers. This study suggested ways to induce active customers by providing after-sales benefit for product reuse to a group of churn customers and to promote the advantages or necessity of using the product by setting the goal of increasing the frequency of use to a group of potential customers. Finally, since the active customer group is a loyal customer, this study proposed an one-on-one marketing to improve product satisfaction.
        4,000원
        13.
        2018.05 구독 인증기관·개인회원 무료
        This study suggested a new real-time traffic signal operation algorithm using combined data of travel time and occupancy rate. This study applied the travel time data to traffic signal control system, and developed the signal operation algorithm based on saturation degree that was calculated using the travel time data. This algorithm calculates a queue length using a delay model, and converts the queue length to the saturation degree. Moreover, it calculates signal timing variables using this combined saturation degree. This study conducted a microscopic simulation for effectiveness evaluation. We checked that the average intersection delay decreased by up to 27 percent. Moreover, we checked that this signal operation algorithm could respond to a traffic condition of oversaturation and loop detector error effectively and usefully. In korea, sectional traffic detection systems are being installed in various ITS projects, such as Advanced Transportation Management System(ATMS) and Urban Transportation Information System(UTIS). This study has important significance in the sense that it is new methodology to accept the sectional detection system in traffic signal control system.
        15.
        2017.07 구독 인증기관·개인회원 무료
        The purpose of this paper is to investigate the usefulness of Flexible Logistics Strategy for coping with the difficulties that logistics industry encountered in the highly competitive market. We define a logistics network model that reflects the current logistics environment of the metropolitan area and suggest the Flexible Logistics Strategy. We investigate the efficiency of the logistics system by comparing the Flexible Vehicle Strategy with other logistics strategies at the various scenarios that can mirror the real world.
        17.
        2016.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        As the development environment is changing with the development of information communication technology, the systems that were used by each service became used with integration. In the process of integrating from existing legacy systems to new system, it should be smoothly integrated or shared, however, it cannot help holding existing technology or component due to significant cost burden for conversion. In this paper, it was not only classified by types with analyzing the various elements that make up legacy system but an approach and monitoring system were developed to each type. After System application results, data's information generated in each process is provided to other system in real time, so that it has not only secured the work efficiency and reliability but also it is made possible by integrating data in various formats for efficient data management, rapid search and tracking to history. With real-time monitoring system developed in this study, It can be very useful in a variety of industries which require real-time monitoring of distributed legacy system data.
        4,000원
        19.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Real-time data reduction pipeline for the Korea Microlensing Telescope Network (KMTNet) was developed by Korea Astronomy and Space Science Institute (KASI). The main goal of the data reduction pipeline is to find variable objects and to record their light variation from the large amount of observation data of about 200 GB per night per site. To achieve the goal we adopt three strategic implementations: precision pointing of telescope using the cross correlation correction for target fields, realtime data transferring using kernel-level file handling and high speed network, and segment data processing architecture using the Sun-Grid engine. We tested performance of the pipeline using simulated data which represent the similar circumstance to CTIO (Cerro Tololo Inter-American Observatory), and we have found that it takes about eight hours for whole processing of one-night data. Therefore we conclude that the pipeline works without problem in real-time if the network speed is high enough, e.g., as high as in CTIO.
        4,000원
        20.
        2012.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        종래의 지구과학 교과서에서는 대중 과학잡지를 비롯한 각종 언론 매체에서 자주 다루는 최신 천문 현상들에 대한 내용이 매우 부실하였다. 2009 개정 과학과 교육과정에서는 이러한 내용들을 적극 수용하자는 것이 주요 개정 방향 중 하나이다. 추가로, 천문학과 물리학의 깊은 연관성에도 불구하고 그동안 지구과학 교과에서는 현대 물리학의 개념, 물리 교과에서는 천문학과의 연관성에 대한 내용이 많이 다루어지지 않았다. 따라서 2009 개정 과학과 교육과정에서는 과학의 융합 개념을 강조하고 있다. 위의 두 가지를 모두 포함하는 분야들 중 하나로서 고에너지 천체의 격변광 현상을 들 수 있다. 본 연구는 e-Science를 이용한 천체 관측의 실시간 자료 전송 및 영상화를 소개하였다. 그 첫 단계의 실험으로서 우리는 국가 연구 교육 시험망의 하나인 KOREN을 이용한 국내 최초의 한 일간 천문 관측 자료의 대용량 자료 전송 실험을 실시하였다. 또한 천문학 및 천체물리학 관측 분야에서 활발하게 진행되는 세계 각국의 e-Science 분야들을 소개하고, 과학탐구활동 및 과학 대중화 활동과 어떻게 연결되어 진행되는지 소개하였다. 아직 걸음마 단계인 국내 천문 분야의 e-Science에 있어서 우리의 실험이 가지는 과학적 및 교육적 의미를 짚어보고, 머지않아 상용화될 Gbps급 인터넷 환경에 있어서 이와 같은 실험의 과학탐구활동 및 과학 대중화 활동에 있어서의 활용을 전망해 보았다.
        5,100원
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