• Korean Journal of Environmental Agriculture
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• 제25권3호
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• pp.195-201
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• 2006

The operational characteristics of anaerobic bioreactors in treating swine wastewater were evaluated upto hydraulic retention time (HRT) of 1 day and organic loading rate (OLR) of $5.1kg-COD/m^3{\cdot}d$ for 200 days. The bioreactors were effective in treating swine wastewaters with COD removal efficiency of $78.9{\sim}81.5%$ and biogas generation of $0.39{\sim}0.59m^3/kg-COD_r$ at OLR of $1.1{\sim}2.2kg-COD/m^3{\cdot}d$. The two-stage ASBF anaerobic bioreactors was effective in treating different characteristics of swine wastewaters since they showed high and stable COD removal efficiency at high OLR due to effective retention of biomass by media and staging. The effects of ammonia on anaerobic digestion were investigated by operating two-stage ASBF reactors using swine wastewaters as influent without and with ammonia removal at HRT of $1{\sim}2$ days and OLR of $2.2{\sim}9.6kg-COD/m^3{\cdot}d$ for 250 days. The COD removal efficiency and biogas generation of two-stage ASBF reactors was decreased by increasing influent ammonia concentrations to 1,580 mg (T-N)/L with increasing OLR to $6.3kg-COD/m^3{\cdot}d$, while those were increased by maintaining influent ammonia concentrations below 340 mg (T-N)/L by MAP precipitation with increasing OLR to $9.6kg-COD/m^3{\cdot}d$. Initial inhibition of ammonia on anaerobic processes was observed at a concentration of 760 mg (T-N)/L and the COD removal efficiency and biogas generation dropped to 1/2 at ammonia concentration ranges of $1,540{\sim}1,870mg$ (T-N)/L. It is essential to remove ammonia in swine wastewaters to an initial inhibition level before anaerobic processes for the effective removal of COD.

• Journal of IKEEE
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• 제28권3호
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• pp.369-374
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• 2024

This paper addresses the design optimization of capacitorless DRAM(one-transistor DRAM., 1T-DRAM), which has gained attention as a next-generation memory technology. To overcome the limitations of conventional capacitor-based DRAM, an asymmetric dual-gate structure is proposed to enhance retention time and overall performance. The zero-temperature coefficient (ZTC) point is set at 1.25 V to minimize performance degradation due to temperature variations. Current-voltage characteristics were analyzed at various temperatures (300K-400K), confirming stable memory operation at the ZTC point, even under temperature fluctuations. The proposed design demonstrates reliable operation at high temperatures, proving the potential for high-efficiency, highly reliable memory technology. As a result, the 1T-DRAM device can make a significant contribution to the development of next-generation memory devices.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• 제29권1호
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• pp.86-93
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• 2015

Globally, wind power development is experiencing dramatic growth and wind power penetration levels are increasing. Wind generation is highly variable in time and space and it doesn't guarantee the system reliability and secure system operation. As wind power capacity becomes a significant portion of total generation capacity, the reliability assessment for wind power are therefore needed. At present, this operational reliability assessment is focusing on a generation adequacy perspective and does not consider transmission reliability issues. In this paper, we propose the critical transmission operating constraint prediction(CTOCP) system with high wind power penetration to enhance transmission reliability.

• Proceedings of the KIEE Conference
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• 대한전기학회 2001년도 춘계학술대회 논문집 전력기술부문
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• pp.58-61
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• 2001

Under restructuring, not only real power pricing but also reactive power pricing is important for the system operation Especially, making a reasonable reactive power pricing is becoming more important than any other time. In this paper, the authors set a proper power factor and price the portion of the reactive power generation that exceeds the power factor. To apply this method to an optimization problem, we developed optimal power flow based on interior point method. By using this IPM for the power system, the System operator can use this strategy for reactive power generation pricing and also the Generators can got the motivation to generate reactive power.

• Journal of Korea Technology Innovation Society
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• 제8권3호
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• pp.1005-1026
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• 2005

On the contrary to the expansion of feasibility studies on public construction and development projects, there is few feasibility studies on S&T, especially large-scale basic research facilities. Based on this critical mind, we tried the first feasibility study on large-scale basic research facilities, that is, the 4th Generation Light Source. First, it is validated whether the construction of 4th Generation Light Source is economically feasible and second, if economically feasible, the optimal place and time for construction are analyzed by using Analytical Hierarchy Process. This research shows that the construction is economically feasible irregardless of scenarios on future bio-medicine industry growth and to construct at Pohang in 2006 is optimal strategy. On the basis of this analysis, the feasibility studies on large-scale basic research facilities are expected to be more expanded and developed.

• The Journal of Korean Institute of Next Generation Computing
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• 제13권1호
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• pp.45-53
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• 2017

The Internet of Things (IoT) technology allows devices connected to the Internet to exchange information without human intervention, and to provide useful services to people. Currently, garbage trucks are regularly dispatched to collect garbage. In such a case, garbage may be less than half of the garbage collection capacity in some area, and garbage may be exceeded in another area so that garbage trucks can not collect all at once. In this paper, we have studied the method of estimating the amount of garbage to be collected and describe the development contents of the product and management system. The prediction of garbage volume was made possible by using IoT technology to measure the volume of garbage in real time. In addition, the measurement values are visibly displayed through the dashboard, so that the amount of garbage generated can be predicted and managed. This will allow IoT technology to help keep street hygiene.

• Journal of Engineering Education Research
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• 제2권1호
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• pp.17-23
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• 1999

Internet application for education has drawn interests in recent time. Usually the method of communication was unidirectional, which means teachers posted educational material on a server and students received them. Even the usage of WWW can't overcome the restriction of unidirectional communication problem. In order to solve this problem, researchers and commercial vendors began to provide packages for bidirectional solution. Those packages are course test generation and evaluation packages using Internet. They provide functionalities of problem generation and score management. In this paper some of those packages are reviewed, and the functionalities of JPGEM (Java Problem Generation and Evaluation Module), which is developed by the author of this paper, are discussed in detail.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제34권6C호
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• pp.619-625
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• 2009

This paper proposes a parallel architecture of a Parity Checksum Generator adopted for packet synchronization and error detection in the ITU-T Recommendation J.83 Annex B. The proposed parallel processing architecture removes a performance bottleneck occurred in a conventional serial processing architecture, leading to significant decrease in processing time for generating a Parity Checksum. The implementation results show that the proposed parallel processing architecture reduces the processing time by 83.1% at the expense of 16% area increase.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• 제13권2호
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• pp.151-156
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• 2000

Effects of alignment layers on pretilt nagle generation and electrical characteristics in nematic liquid crystal(NLC) by using photo-alignment techniques on polyimide PI) surface with side chain were studied. The generated pretilt angle of the NLC on rubbed PI surface with 1-layer is almost the same as that with the 2-layers. However, the generated pretilt angle of the NLC on photo-induced PI surface with 2-layers is larger than that with the 1-layer. The different mechanism of pretilt generation in NLC was observed on the rubbing and photo-alignment method. Therefore, the pretilt angle of the NLC on photo-induced PI surface is attributed to surface roughness due to photo-dissociation on the polymer with UV light irradiation on PI surface. We observed the same characteristics of voltage-transmittance (V-T) and response time for 1- and 2-layers on PI surface. Consequently, we sugest that the VHR of photo-aligned TN-LCD is higher than that of the rubbing-aligned TN-LCD.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제32권6B호
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• pp.325-333
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• 2007

An OS requires the device driver to control hardware IPs at application level. Development of a device driver requires specific acknowledge for target hardware and OS. In this paper, we present a system which generates a device driver together with an interface circuit. In the proposed system, an efficient device driver is generated by selecting a basic device driver skeleton, a function module code, and a header file table from the pre-constructed library and an interface circuit is constructed such that the generated device driver operates correctly. The proposed system is evaluated by generating a TFT-LCD device driver on the ARM922T core with 3.5 inch Samsung TFT-LCD in ARM-Linux environment. Experiment result shows that the writing time on the LCD is decreased by 1.12% and the compiled code size is increased by 0.17% compared to the manually generated one. The automatically generated device driver has no performance degradation in the latency of hardware control at the application program level. The system development time can be reduced using the proposed device driver generation system.