• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.419-422
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• 2011

In this paper a dual-input self-powered power management system is proposed for low-power applications. The system is powered by merging the energy from a PZT vibration element and a solar cell. The proposed system consists of a charge pump for increasing the output voltage of a solar cell, a rectifier for DC conversion of the PZT output and a power management circuit for merging and managing the harvested energy. The performance of the design circuit has been verified through extensive simulation using a 0.18um CMOS technology. The chip area is $295um{\times}275um$.

• Journal of Environmental Science International
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• v.16 no.4
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• pp.505-521
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• 2007

This study estimated response of water duality and pollutant behavior according to the discharge and reuse of treated wastewater by three-dimensional eco-hydrodynamic model, and suggest plan that water quality management and environmental restoration in the coastal area including urban stream of Yeosu, Korea. Dispersions of low-saline water and COD by treated wastewater loads (design facility capacity, about $110,000m^3/d$) were very limited in near of effluent site. Nutrients, however, increase compared to the other water quality factors, especially total nitrogen was very sensitive to input loads. When reuse some of treated wastewater to Yeondeung stream, nitrogen was big influence on estuarine water quality. Although current characteristics of treated wastewater such as discharge and water quality were negligible to the change of marine environment, effluent concentration of COD, TN and TP, especially 40% of TN, are reduced within the allowable pollutant loads for satisfy environmental capacity and recommended water duality criteria. Also, controls of input point/non-point sources to Yeondeung stream and base concentration of pollutants in coastal sea itself are very necessary.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.12
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• pp.960-966
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• 2013

In this study, operation data from an actual plant in M city were analyzed to evaluate effects of water supply into sewage sludge on the co-incineration of municipal solid waste (MSW) and sewage sludge. Design capacity of the stoker incinerator is 50 m3/day. Maximum portion of sewage sludge in the total waste input was 20%. According to this research, moisture content increase up to 85% of sewage sludge could be possible by water supply on MSW input to the incinerator. Therefore, stable operation of incinerator could be achieved. As water was added into sewage sludge up to 85%, input quantity of sewage sludge to frequency (Hz) was similar to theoretical input. Also, it is concluded that stable management of incinerator without leachate combustion and damages of refractory bricks and castable could be achieved by the reduction of low heating value.

• Journal of Korean Society of Forest Science
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• v.109 no.4
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• pp.521-531
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• 2020

In order to identify the economic impacts of forest-related industry on the national economy in general and the linkages between forestry and its related industries, an input-output analysis was conducted using the 2015 Input-Output Tables of the Bank of Korea. Production inducement effects are relatively high in paper products, lumber, and silviculture and relatively low in other wood industries. Value-added inducement effects are relatively high in silviculture and log production. With respect to the wood products industry, forward linkage effects are higher and backward linkage effects are lower. A Ritz-Spaulding multiplier analysis revealed that the growth of wood products production has only a modest impact on the growth of forestry. How to increase the linkage between forestry and the wood products industry is one of the most important policy tasks in Korea, given that it affects forest ecosystem management and climate change mitigation efforts.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.3
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• pp.63-69
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• 2017

This paper presents a highly efficient power management system for UAV-drones. For free from the battery cell-balancing issue, the proposed system allows the drone to utilize a single-cell Li-Po battery. To realize low-voltage input of 3.7V, the switch-mode step-up DC-DC converter is optimally designed with high power efficiency. The prototype DC-DC converter was implemented with an output voltage of 5V, which will be provided to digital parts of the drone. The power efficiency was measured to be max. 91.3% with low surface temperature. The measured line and load regulations were 0.02V/V and 0.15V/A, respectively. Thanks to the proposed power management system, the available time-to-fly of the drone is expected to be significantly extended in virtue of the enhanced power efficiency.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.2
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• pp.113-118
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• 2016

Project management is a tool for smooth operation during a full cycle from the design to normal operation including the schedule, document, and budget management, and document management is an important work for big projects such as the JRTR (Jordan Research and Training Reactor). To manage the various large documents for a research reactor, a project management system was resolved, a project procedure manual was prepared, and a document control system was established. The ANSIM (Advanced Nuclear Safety Information Management) system consists of a document management folder, document container folder, project management folder, organization management folder, and EPC (Engineering, Procurement and Construction) document folder. First, the system composition is a computerized version of the Inter-office Correspondence (IOC), the Document Distribution for Agreement (DDA), Design Documents, and Project Manager Memorandum (PM Memo) works prepared for the research reactor design. Second, it reviews, distributes, and approves design documents in the system and approves those documents to register and supply them to the research reactor user. Third, it integrates the information of the document system-using organization and its members, as well as users' rights regarding the ANSIM document system. Throughout these functions, the ANSIM system has been contributing to the vitalization of united research. Not only did the ANSIM system realize a design document input, data load, and search system and manage KAERI's long-period experience and knowledge information properties using a management strategy, but in doing so, it also contributed to research activation and will actively help in the construction of other nuclear facilities and exports abroad.

• Journal of Sensor Science and Technology
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• v.29 no.5
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• pp.283-292
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• 2020

Current sensors that use a Hall element and Hall IC to measure the magnetic fields generated in steel silicon core gaps do not distinguish between direct and alternating currents. Thus, they are primarily used to measure direct current (DC) in industrial equipment. Although such sensors can measure the DC when installed in expensive equipment, ascertaining problems becomes difficult if the equipment is set up in an unexposed space. The control box is only opened during scheduled maintenance or when anomalies occur. Therefore, in this paper, a method is proposed for facilitating the safety management and maintenance of equipment when necessary, instead of waiting for anomalies or scheduled maintenance. A Bluetooth 4.0 low-energy current-sensor system based on near-field communication is used, which compensates for the nonlinearity of the current-sensor output signal using a piecewise linear model. The sensor is controlled using its generic attribute profile. Sensor nodes and cell phones used to check the signals obtained from the sensor at 50-A input currents showed an accuracy of ±1%, exhibiting linearity in all communications within the range of 0 to 50 A, with a stable output voltage for each communication segment.

• Journal of Welding and Joining
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• v.25 no.1
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• pp.42-48
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• 2007

For high performance and structural stability, application of high strength steel has continuously increased. However, the change of the base metal gives rise to problems with the accuracy management of the welded structure. It is attributed to the martensite phase transformation of the high strength low alloy steel weldment. The purpose of this study is to establish the predictive equation of transverse shrinkage and residual stress for the HY-100 weldment. In order to do it, high speed quenching dilatometer tests were performed to define a coefficient of thermal expansion(CTE) at the heating and cooling stage of HY-100 with various cooling rates. Uncoupled thermal-mechanical finite element(FE) models with CTE were proposed to evaluate the effect of the martensite phase transformation on transverse shrinkage and residual stresses at the weldment. FEA results were verified by comparing with experimental results. Based on the results of extensive FEA and experiments, the predictive equation of transverse shrinkage and longitudinal shrinkage force at the HY-100 weldment were formulated as the function of welding heat input/in-plane rigidity and welding heat input respectively.

• Journal of Digital Convergence
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• v.10 no.11
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• pp.371-376
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• 2012

In this paper, we propose a new data coding method and its circuits for minimizing data transition in text image. The proposed circuits can solve the synchronization problem between input data and output data in the modified LVDS algorithm. And the proposed algorithm is allowed to transmit two data signals through additional serial data coding method in order to minimize the data transition in text image and can reduce the operating frequency to a half. Thus, we can solve EMI(Electro-Magnetic Interface) problem and reduce the power consumption. The simulation results show that the proposed algorithm and circuits can provide an enhanced data transition minimization in text image and solve the synchronization problem between input data and output data.

• Journal of the Korean Society of Safety
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• v.26 no.5
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• pp.105-109
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• 2011

Since a severe accident, which happens in low frequency, can cause serious damages, the interests in off-site consequence analysis for a nuclear power plant have been increased after Chernobyl, TMI and Fukushima accidents. Consequences, which are the effects on health and environment caused by released radioisotopes, are evaluated using MACCS II code based on the method of Level 3 PSA. To perform a consequence analysis for the reference plants, the input data of the code were generated such as meteorological data, population distribution, release fractions, and so on. Using these input data, acute and lifetime dose as an organ, CCDF for early fatalities and latent cancer fatalities, and average individual risk were analyzed by using MACCS II code in this study. These results might contribute to establishing accident management plan and quantitative health object.