• Journal of the Korea Society for Simulation
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• v.20 no.3
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• pp.49-58
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• 2011

The workloads of facilities and laborers are important for the capacity planning in a factory. They are always referenced whenever a factory develops a new product, increases the production quantity and makes a plan of new investment. There are many measuring methods for estimating the workload effectiveness of facilities and laborers. In this paper, various measuring methods including survey, work sampling, micro-motion study, data gathering from ERP system and simulation, are analyzed for comparing the accuracy of workload. This case study is conducted in a Korean company that produces semiconductor parts like leadframe and packaging substrate.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.6
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• pp.517-524
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• 2017

The objective of this research is to improve the efficiency of data collection from many machine components on smart factory floors using IoT(Internet of things) techniques and cloud platform, and to make it easy to update outdated diagnostic schemes through online deployment methods from cloud resources. The short-term analysis is implemented by a micro-controller, and it includes machine-learning algorithms for inferring snapshot information of the machine components. For long-term analysis, time-series and high-dimension data are used for root cause analysis by combining a cloud platform and multivariate analysis techniques. The diagnostic results are visualized in a web-based display dashboard for an unconstrained user access. The implementation is demonstrated to identify its performance in data acquisition and analysis for rotating machinery.

• Journal of Environmental Science International
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• v.14 no.1
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• pp.71-80
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• 2005

Soil is one of the most fundamental elements as well as with water and air in studies associated with the environment, in addition, it is one of the important environmental mediums that constructs a basis of the bio­logical system and performs various roles of matter circulation. This study was carried out in Seoul, in May 2000 to evaluate variation in the concentration levels and distribution characteristics for PAH compounds in soil. Soil samples were collected from 33 sites covering traffic, factory, incineration and mountain groups and the PAHs were analyzed. The results show a wide dis­tribution range of PAHs concentrations between 14.66 ng/g and 1,219.35 ng/g. The highest concentration levels exist at Sungsu-2 of the factory group (FS-2). Daemo-3 of the Mountain group (MD-3) presents the lowest levels as compared with the other sites. PAH compounds including mutagenic and carcinogenic materials show high concentrations in the traffic and factory groups and a high ratio in the mountain group. Besides, these compounds absorbed with micro particles might be spread out over a wide region associated with particles' movement and diffusion. After principal component analysis of the soil samples, the results indicated that the sources of PAHs in the soil were divided into two groups, pesticides and vehicles.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.4
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• pp.211-218
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• 2018

Recently, various technologies related to IIoT are introduced continuously due to the spread of IoT and smart factory industries. This paper proposes the construction of a two-way wireless network system for monitoring plant equipment using these various technologies. The main technologies used in this thesis are design techniques for micro sensor nodes to monitor facility conditions at various sites, MQTT technology for wireless communication between local server and sensor nodes and Node-RED based design technologies, which store data collected and can be easily presented to users via wired and wireless wires. In addition, a wireless two-way camera system was also implemented in which the screen images of the site can be viewed in the situation room according to the instructions of the situation room when determining abnormal conditions.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.4
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• pp.403-410
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• 2016

Materials made of metals have their own manifest resonant frequencies. Using this property, the quality test of products from the factory can be performed. An impact is applied to the product and the frequencies of the sound and/or vibration are measured using high-end equipments. They use a general purpose computer or a DSP(: Digital Signal Processor)-based stand-alone system which is usually too large in-size to carry and expensive to build. In this paper, we introduce a system that is developed based on a MSP430 MCU(:Micro-Controller Unit) from TI(: Texas Instruments). The ultra-low power MSP430 MCUs make it possible to make a frequency analyzer in a very small size without the need of using a large-size battery. The proposed system can be used in situations where the frequency analyzer should be carried easily with an investigator and should be built at low cost sacrificing some accuracy. We implemented the system using a launchpad supplied by TI and could confirm that the proposed system could identify with a high-accuracy the frequencies of various artificial and natural sounds.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.1243-1247
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• 1996

In this paper, a small PLC system is designed and developed for the distributed building control and fire control system. It uses 8031, a 8-bit micro controller from Intel Inc. The size of the PLC is $7cm{\times}8cm$ and the PLC can accept 4 sensor inputs and drive 4 relay outputs, which operates at 24V. Multiple access of PLC by one host computer is implemented by assigning a unique 10 to each PLC, which ranges from 0 to 126. The operation starts by sending a command packet from host computer to a PLC and the PLC of the same 10 fetches the command packet by comparing the first byte of the command packet with its own 10. The PLC is programmed to perform a various functions and the function is selected by the content of the command byte, which is the second byte of the command packet. The third byte, which is the last byte, is a checksum byte. The checksum byte is the sum of the first byte and the second byte and is used to detect the communication error. Depending on the content of the command byte, PLC performs the desired function and returns the response packet back to the host computer. The response packet is also a three-byte packet, 10 byte, response byte and checksum byte. For the independent operation of PLC without being controlled by the host computer, variable length RULE data packet is sent to PLC. In case the communication line is broken, the PLC perform the independent operation by referencing the RULE data. The applicable areas are; building automation system, distributed factory automation, measurement of temperature of toxic or dangerous area.

• Proceedings of the Korean Society of Computer Information Conference
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• 2015.01a
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• pp.165-166
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• 2015

본 논문에서는 식물공장에서 사용할 수 있는 파장별 광원제어가 가능한 조명장치의 설계하고 구현하고자 한다. 식물의 생장에 필수적인 광원의 파장에 따라 생장에 다양한 영향을 미치게 된다. 따라서 본 논문에서는 식물 생장에서 필요한 다양한 파장의 빛을 공급할 수 있는 식물공장용 조명시스텡을 개발한다. 조명시스템은 마이크로 컴퓨터를 이용하여 적, 청, 녹색 3색 LED를 PWM제어하여 광량과 세기를 제어하고, 공급된 광량을 적산하여 조사된 광량을 확인할 수 있도록 구성하였다. 본 조명 시스템은 태양광 이용형 식물공장의 보조광원으로 사용 가능하며, 완전제어형 식물공장에서 사용이 가능하다.

• Journal of Biosystems Engineering
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• v.15 no.4
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• pp.328-338
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• 1990

The objective of this study was to develop automatic systems of nutrient solution management for optimal nutrient solution environment and labor saving in water culture which enables factory crop production. In this study, an automatic control system and its driving program are developed to prepare, supply, and recover nutrient solution and to keep the optimal solution concentration level using microcomputers. Based on this study, the following conclusions are obtained: 1. The concentration measured by the system using oscillating circuit designed and built in this study, gave good agreements with the actual nutrient solution. 2. In water culture, the period of 12 hours for measuring concentration, pH, and temperature of the nutrient solution was optimum. Addition of control solution due to the decrease of the nutrient solution concentration is required in every 3 to 5 days. 3. It is estimated that the period of the whole solution change is 15 days, however, further research is needed to assure it. In addition, this period must be shortened in the future. 4. Both the hardware and software of the developed optimal nutrient solution control system in the water culture are working very well, however, it is necessary to develop a more economical one-chip micro controller to substitute for the microcomputer.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.361-364
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• 2008

The Application Model in Wireless Sensor Networks(WSNs) consist of wireless sensor network based on sensor hardwares which is combined the micro-controller, chipset for wireless communication and sensors, middleware for dealing with data processing and user application for common service. Applications in WSN have been applied for environmental monitoring, smart factory and have concentrated the services based on remote monitoring applications which is difficult to watch the situation by human. In this paper, we described the construction model for applying for the Ubiquitous disaster prevention system and deal with its conformity. The proposed system includes the selecting the wireless sensor hardware, routing technique for u-Disaster Prevention, composition of middleware and web-interface for application services.

• Journal of Bio-Environment Control
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• v.17 no.4
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• pp.252-260
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• 2008

This study was conducted to observe the characteristics of mineral nutrient uptake of single-node cutting rose 'Versilla' and to determine optimal nutrient solution control method for soilless culture of 'Versilla' in a closed hydroponic system. Nutrient solution was managed by five different control methods: macro- and micro-element control in aeroponic system (M&M), macroelement control in aeroponic system (M), nutrient solution supplement in aeroponic system (S); electrical conductivity (EC) control in aeroponic system(EC-A); EC control in deep flow technique system(EC-D). The concentration of $NO_3$-N exceeds optimal range whereas P and Mg decreased at the later stage of plant growth with the EC control method, EC-A and EC-D. The overall mineral nutrient content increased with S. On the other hand the nutrient content at the root environment was maintained optimal with M&M and M. The nutrient solution control methods had significantly effect on the cut-flower quality. In the M&M and M, flower length, fresh weight and root activity were higher than those with the other mineral nutrients control methods. The maximal efficiency of photochemistry (Fv/Fm) was higher for M&M, M and S than that with EC-A and EC-D. Based on the above results, it is highly recommended to control nutrient solution by mineral nutrient control methods (M&M and M) in a closed hydroponic system for single-node cutting rose, 'Versillia'.