• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.3
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• pp.61-71
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• 2014

As the occupancy rate of the flash memory increases in the storage media market for the embedded system and the semi-conductor industry grows, the demand and supply of flash memory is increasing by a big margin. They are especially used in large quantity in the smart phones, tablets, PC, SSD and Soc(System on Chip) etc. The flash memory is divided into the NOR type and NAND type according to the cell arrangement structure and the NAND type is divided into the SLC(Single Level Cell) and MLC(Multi Level Cell) according to the number of bits that can be stored in each cell. Many tests have been performed on NOR type such as BIST(Bulit-In Self Test) and BIRA(Bulit-In Redundancy Analysis) etc, but there is little study on the NAND type. For the case of the existing BIST, the test can be proceeded using external equipments like ATE of high price. However, this paper is an attempt for the improvement of credibility and harvest rate of the system by proposing the BIST for the MLC NAND type flash memory of Finite State Machine structure on which the pattern test can be performed without external equipment since the necessary patterns are embedded in the interior and which uses the MLC NAND March(x) algorithm and pattern which had been proposed for the MLC NAND type flash memory.

• Journal of Environmental Policy
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• v.6 no.1
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• pp.61-81
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• 2007

Types of agricultural policy can be catagorized into two general cases: price and income supports. Income supports are any government program designed to provide farmers with higher incomes than they would receive otherwise. These direct cash payments to farmers are known as "deficiency payment" or "direct payment" because they compensate the farmer for the failure of the market to provide farmers with adequate prices. The direct payment to environment-friendly agriculture is a form of income supports for the agriculture production using less pesticides and chemical fertilizers. Because no significant regulation exists on the use of fertilizers substituting chemical fertilizers for crop, the role of the payment on reducing environmental impacts of agriculture is not entirely clear. This uncertainty is likely to be particularly severe in the case that farmers with low-quality land showing greater demand for fertiliser have an incentive to transition to environment-friendly agriculture. The paper shows the case of the current payment system in Korea.

• Journal of Internet Computing and Services
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• v.21 no.1
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• pp.237-246
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• 2020

this paper, a data modeling method based on decision-making conditions is proposed for making combat and battlefield management systems to be intelligent, which are also a decision-making support system. A picture of a robot seeing and perceiving like humans and arriving a point it wanted can be understood and be felt in body. However, we can't find an example of implementing a decision-making which is the most important element in human cognitive action. Although the agent arrives at a designated office instead of human, it doesn't support a decision of whether raising the market price is appropriate or doing a counter-attack is smart. After we reviewed a current situation and problem in control & command of military, in order to collect a big data for making a machine staff's advice to be possible, we propose a data modeling prototype based on decision-making conditions as a method to change a current control & command system. In addition, a decision-making tree method is applied as an example of the decision making that the reformed control & command system equipped with the proposed data modeling will do. This paper can contribute in giving us an insight of how a future AI decision-making staff approaches to us.

• Safety and Health at Work
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• v.10 no.4
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• pp.452-460
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• 2019

Background: Monitoring and control of PM_2.5 are being recognized as key to address health issues attributed to PM_2.5. Availability of low-cost PM_2.5 sensors made it possible to introduce a number of portable PM_2.5 monitors based on light scattering to the consumer market at an affordable price. Accuracy of light scatteringe-based PM_2.5 monitors significantly depends on the method of calibration. Static calibration curve is used as the most popular calibration method for low-cost PM_2.5 sensors particularly because of ease of application. Drawback in this approach is, however, the lack of accuracy. Methods: This study discussed the calibration of a low-cost PM_2.5-monitoring device (PMD) to improve the accuracy and reliability for practical use. The proposed method is based on construction of the PM_2.5 sensor network using Message Queuing Telemetry Transport (MQTT) protocol and web query of reference measurement data available at government-authorized PM monitoring station (GAMS) in the republic of Korea. Four machine learning (ML) algorithms such as support vector machine, k-nearest neighbors, random forest, and extreme gradient boosting were used as regression models to calibrate the PMD measurements of PM_2.5. Performance of each ML algorithm was evaluated using stratified K-fold cross-validation, and a linear regression model was used as a reference. Results: Based on the performance of ML algorithms used, regression of the output of the PMD to PM_2.5 concentrations data available from the GAMS through web query was effective. The extreme gradient boosting algorithm showed the best performance with a mean coefficient of determination (R²) of 0.78 and standard error of 5.0 ㎍/㎥, corresponding to 8% increase in R² and 12% decrease in root mean square error in comparison with the linear regression model. Minimum 100 hours of calibration period was found required to calibrate the PMD to its full capacity. Calibration method proposed poses a limitation on the location of the PMD being in the vicinity of the GAMS. As the number of the PMD participating in the sensor network increases, however, calibrated PMDs can be used as reference devices to nearby PMDs that require calibration, forming a calibration chain through MQTT protocol. Conclusions: Calibration of a low-cost PMD, which is based on construction of PM_2.5 sensor network using MQTT protocol and web query of reference measurement data available at a GAMS, significantly improves the accuracy and reliability of a PMD, thereby making practical use of the low-cost PMD possible.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.1
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• pp.84-90
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• 1986

An experiment was conducted to know the effects of planting dates (March 5, 15, and 25 and April 4) and transparent polyethylene (P.E.) film treatments(tunnel, tunnel slit, and mulch) on air and soil temperatures and growth and yield of a sweet corn variety, Great Bell. Maximum air and soil temperatures and minimum air and soil temperatures were greater at tunnel>tunnel slit>mulch in that order. Differences in maximum air and soil temperatures among the P.E. film treatments were much greater than those in minimum air and soil temperatures. However, when film was opened due to high air temperature over 40$^{\circ}C$ in the tunnel, air temperature was similar but soil temperature was lower com-pared to mulch. High temperature stress could be avoided in tunnel slit without opening film by increase in the number of slits. Cold damage of corn seedlings was avoided by tunnel and reduced by tunnel slit, and frost-damaged seedlings under the mulch were recovered in few days. The number of days from planting to silking was reduced as planting date delayed. At early plantings, tunnel enhanced early growth and silking, but it delayed at late plantings because tunnel was opened during the most of day time due to high temperature. Black streaked dwarf virus(BSDV) disease was more severe at early plantings and it was reduced in tunnel slit at late plantings because plants were grown under the film at the time of infection. The number of marketable ears was similar among all treatments except mulch at March 5 planting where BSDV was severely infected. Gross income was high in tunnel and tunnel slit at March 25 planting which had more larger marketbale ears and tunnel and tunnel slit at March 5 planting which had higher market price.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.2
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• pp.117-121
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• 1990

A sweet corn hybrid, Golden Cross Bantam 70, was grown at 5 plant populations (5,000, 6,000, 7,000, 8,000, and 9,000 plants/10a) under the transparent P .E. film mulch to find the best yield evaluation method. Plant population did not affect early plant growth, culm length, ear height, and silking date. However, number of tillers at harvest decreased but leaf area index increased with increased plant population. Marketable ears were divided into two classes; the first grade of which husked ear weight over l50g (unhusked ear weight 230g) and the second grade of which husked ear weight between 100 and 150g (unhusked ear weight between 180 and 230g) according to the whole sale market price. Average length, thickness, and weight of marketable ears over 100g of husked ears decreased with increased plant population. The proportion of ears over 150g decreased with increased plant population. However, total number and weight of marketable ears and gross income per 10a calculated considering weight and number of ears increased with plant population. There were highly positive correlations between gross income and ear number or ear weight per unit area. At high plant populations the number of marketable ears was overestimated but ear weight underestimated compared with gross income. Dry matter yield of stover increased with increased plant population and ranged 755-944kg/10a with 20.7-24.5% dry matter content. Rice black-streaked dwarf virus infection rate was 10.6-14.9%, but it was not related to plant population.

• Korean journal of communication and information
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• v.48
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• pp.63-89
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• 2009

The contents provided by the terrestrial broadcasters have governed the market based on their excellent quality in Korea. In spite of the launching of various pay TV services focusing on multi-channel, it is not yet easy to find out the substitutionary pay TV channels for the terrestrial. Therefore, the real time retransmission of the terrestrial channels brings about the crucial effects on the pay TV's competency, especially on the new media as the invisible barrier. So it is frequently proposed to change the aim of the retransmission policy from the universal access to the promotion of media industries. The retransmission can be divided into two types as the must carry and retransmission consent. In Korean situation, keeping or reducing the must carry channel would be appropriate rather than expanding them. However, periodic investigation into the public effects of the must carry is necessary, instead of it. Moreover, the rational and fair monetary compensation for the commercial channels(MBC, SBS, KBS2) is arising as the bottle neck in the retransmission agreements between the broadcasters. The conjoint analysis was carried out to estimate the welfare growth from the retransmission, based on the stated preference from the audiences' point of view. For must carry channels, it was certified as the 'win-win' strategy for both sides and audiences. For the commercial channels, it is revealed to be beneficial to the audiences. Thereafter, the standards for the rational price were suggested to promote the retransmission. This can contribute for inspiring the dynamic vitality to the media industry by reinforcing the contents competencies and for establishing the long term growth strategies.

• The Journal of the Korea Contents Association
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• v.11 no.10
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• pp.217-233
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• 2011

In this study, we have examined how the potential users of IT convergence product use the external information sources for purchasing decision focusing on a case of smartphone. Although the specifications and price of IT convergence products, such as smartphone, tablet pc, and smart TV, are considered as major criteria for purchasing decision, the competitiveness of these factors have disappeared as many companies launch similar products in the market. External information sources play a significant role to differentiate the alternatives by offering value-added experience information. The effect of external information sources becomes stronger for experience and high-involvement product whose performance can be evaluated through only users' direct experience. In this study, we categorized the external information sources for smartphone into five; company ads, personal network, expert group, consumers, and media. Through an empirical study with potential smartphone users, we verified how these external information sources affect users' purchasing decision in the perspective of the perceived attributes of information source, quality of information, and individual's characteristics based on self-regulatory theory.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.252-263
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• 2018

In this research, we performed a SWOT analysis to analyze the feasibility of cultivating tropical fruits in Korea, using the mango as a case study. The opportunities for domestic tropical fruit (mango) cultivation are that the domestic cultivation environment is improving due to global warming, the consumer market is expanding due to the increase in domestic demand, and some local governments are supporting the cultivation of tropical fruits as a new high-income crop. The strengths are that it is possible to produce high quality fresh fruits in Korea and that they are still distributed in small quantities, so they can be differentiated from imported ones. There are regular customers and the mango is recognized as a medicinally functional fruit. The threats are that the price competitiveness of imported goods is likely to be further strengthened due to the implementation of the FTA and that it is difficult to cope with the unpredictable climate changes, such as heavy snowfall and extremely cold weather. The weak points are that the initial investment cost is high, the operating costs such as heating bills are also very high, and there is no supply system for the chemicals, fertilizers and cultivation technology required for tropical fruits. In order for tropical fruits such as mangoes to become major fruits, we must make full use of these strengths and opportunities while, at the same time, complementing the weaknesses and eliminating the threats in the value chain.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.117-124
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• 2017

A Smart Grid is a system that can efficiently use energy by exchanging real-time information in both directions between a consumer and a power supplier using ICT technology on an existing power network. DR(Demand response) is an arrangement in which electricity users can sell the electricity they save to the electricity market when the price of electricity is high or the power system is crisis. In this study, we developed a power meter data transmission device and power IT system that measure the demand information in real-time using a smart meter and transmit it to a cloud server. The power meter data transmission device developed in this study uses alight sensor connected to a Raspberry Pi 3 to measure the number of blinking lamps on the KEPCO meter per unit of power, in order to provide reliable data without any measurement errors with respect to the KEPCO power data. The power measurement data transmission device uses the standard communication protocol, OpenADR 2.0b. The measured data is transmitted to the power IT system, which consists of the VEN, VTN, and calculation program, via the LTE WiFi communication network and stored in its MySQL DB. The developed power measurement data transmission device issues a power supply instruction and performs a peak reduction DR when a power system crisis occurs. The developed power meter data transmission device has the advantage of allowing the user to adjust it every 1 minute, where as the existing smart metering time is fixed at once every 15 minutes.