• Journal of Korean Society of Water and Wastewater
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• v.38 no.1
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• pp.29-38
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• 2024

Wastewater management is increasingly emphasizing economic and environmental sustainability. Traditional methods in sewage treatment plants have significant implications for the environment and the economy due to power and chemical consumption, and sludge generation. To address these challenges, a study was conducted to develop the Intermittent Cycle Extended Aeration System (ICEAS). This approach was implemented as the primary technique in a full-scale wastewater treatment facility, utilizing key operational factors within the standard Sequencing Batch Reactor (SBR) process. The optimal operational approach, identified in this study, was put into practice at the research facility from January 2020 to December 2022. By implementing management strategies within the biological reactor, it was shown that maintaining and reducing chemical quantities, sludge generation, power consumption, and related costs could yield economic benefits. Moreover, adapting operations to influent characteristics and seasonal conditions allowed for efficient blower operation, reducing unnecessary electricity consumption and ensuring proper dissolved oxygen levels. Despite annual increases in influent flow rate and concentration, this study demonstrated the ability to maintain and reduce sludge production, electricity consumption, and chemical usage. Additionally, systematic responses to emergencies and abnormal situations significantly contributed to economic, technical, and environmental benefits.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.1
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• pp.115-125
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• 2011

Cryptographic hash functions are also called one-way functions and they ensure the integrity of communication data and command by detecting or blocking forgery. Also hash functions can be used with other security protocols for signature, authentication, and key distribution. The SHA-1 was widely used until it was found to be cryptographically broken by Wang, et. al, 2005. For this reason, NIST launched the SHA-3 competition in November 2007 to develop new secure hash function by 2012. Many SHA-3 hash functions were proposed and currently in review process. To choose new SHA-3 hash function among the proposed hash functions, there have been many efforts to analyze the cryptographic secureness, hardware/software characteristics on each proposed one. However there are few research efforts on the SHA-3 from the point of power consumption, which is a crucial metric on hardware module. In this paper, we analyze the power consumption characteristics of the SHA-3 hash functions when they are made in the form of ASIC hardware module. Also we propose power efficient hardware architecture on Luffa, which is strong candidate as a new SHA-3 hash function. Our proposed low power architecture for Luffa achieves 10% less power consumption than previous Luffa hardware architecture.

• Transactions of Materials Processing
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• v.17 no.8
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• pp.594-599
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• 2008

This paper presents a micro air pump based on the synthetic jet to supply reactant at the cathode side for micro fuel cells. The synthetic jet is a zero mass flux device that converts electrical energy into the momentum. The synthetic jet actuation is usually generated by a traditional PZT-driven actuator, which consists of a small cylindrical cavity, orifices and PZT diaphragms. Therefore, it is very important that the design parameters are optimized because of the simple configuration. To design the synthetic jet micro air pump, a numerical analysis has been conducted for flow characteristics with respect to various geometries. From results of numerical analysis, the micro air pump has been fabricated by the PDMS replication process. The most important design factors of the micro air pump in micro fuel cells are the small size and low power consumption. To satisfy the design targets, we used SP4423 micro chip that is high voltage output DC-AC converter to control the PZT. The SP4423 micro chips can operate from $2.2{\sim}6V$ power supply(or battery) and is capable of supplying up to 200V signals. So it is possible to make small size controller and low power consumption under 0.1W. The size of micro air pump was $16{\times}13{\times}3mm^3$ and the performance test was conducted. With a voltage of 3V at 800Hz, the air pump's flow rate was 2.4cc/min and its power consumption was only 0.15W.

• Journal of Korea Multimedia Society
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• v.11 no.10
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• pp.1392-1402
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• 2008

Home gateway is always full-powered for ubiquitous home services, and consumes much energy yearly. Power-saving algorithm to conserve this energy must reduce the energy consumption and preserve always-on services. Our algorithm predicts current idle period using the history of the past idle period when the idle period starts, and then determines whether the power mode is changed to the saving mode or not. On the power saving mode, it processes the simple protocol data for network control using proxying with no wakeup. And it changes the power mode to active mode when user's traffic exists. As the results of the simulation using real traffic, our algorithm saves the energy consumption from 14% to 49% as compared with existing method.

• Journal of the Korean Society for Railway
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• v.15 no.4
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• pp.329-333
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• 2012

In this paper, By the time that the tilting technology is adopted in railway rolling stock, we analyzed quantitatively energy saving by reducing the power consumption with the reduction of the operation time through the speed improvement and suggested the necessity to introduce tilting technology in the domestic rail vehicles. To achieve this purpose, the effect of energy saving by comparing and analyzing the power consumption during the operation by TTX HANVIT 200 and 8200 electric locomotives to pull the trains on the same line was suggested and the efficiency of the main devices was compared and analyzed by measuring the power consumption by a single unit. As the energy saving is the world topic, the studies on reducing energy usage goes on constantly in many areas. In addition, as of the time to improve the conventional tracks to speed up and change the signals, Tilting technology will be contributed to the management environment by enlarging the passengers' demand through the reduction of the operation time and saving energy using the existing infrastructure.

• Journal of the Korean Vacuum Society
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• v.12 no.2
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• pp.93-104
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• 2003

For evaluation of durability of low vacuum pumps, it is required to examine the performance and degradation of low vacuum pumps. Pump degradation may result from abnormalities associated with the performance in many areas of pump operation. The diagnostics method can be used to monitor the pump performance in the semi-conductor process line. Based on the mechanical defect of the pump, the dynamic response and reliability of the system for performance test, and the dynamic characteristics of the pump were experimentally assessed. The theoretical work rate for the compression process in the pump was calculated, and then the efficiency of the pump associated with the power consumption was evaluated. This analysis will be useful in detecting pump degradation with increasing the power consumption. To determine the predominant factors of pump degradation, it is important to evaluate the entire pumping system. We studied vibration, dynamic pressure, pumping speed, and power consumption of low vacuum pumps. Our results can be utilized for the future research on the evaluating technology of durability of low vacuum pumps.

• KIEE International Transactions on Power Engineering
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• v.2A no.4
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• pp.136-144
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• 2002

Load models are very important for improving the accuracy of stability analysis and load flow studies. Various loads are connected to a power bus and their characteristics of power consumption change with voltage and frequency. Thus, the effect of voltage/frequency changes must be considered in load modeling. In this work, artificial neural networks-ANNs- were used to construct the component load models for more accurate modeling. A typical residential load was selected and subjected to a test under variable voltage/frequency conditions. Acquired data were used to construct component models by ANNs. The aggregation process of separately determined load models is also presented in the paper. Furthermore, this paper proposes a method to transform a single load model constructed by the aggregation method into a mathematical load model that can be used in traditional power system analysis software.

• Journal of Distribution Science
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• v.22 no.8
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• pp.87-98
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• 2024

Purpose: This study aimed to examine the influence of private label cues, including store image, product design, price promotion, and origin image, on consumers repurchase intention by mediating consumption value from a distribution perspective. Additionally, it explored nationality's moderating role in the relationship between consumption value and repurchase intention. Research design, data and methodology: Drawing on the SOR model, data were collected from 246 consumers who had purchased private-label products in the past month. Structural equation modeling analysis was employed to test hypotheses using AMOS and SPSS. Results: Findings revealed that cues significantly impact consumers' perception of consumption value, influencing repurchase intention. Price promotion directly affected repurchase intention, while other cues indirectly influenced it through consumption value mediation. Nationality moderated the relationship between consumption value and repurchase intention, with Korean consumers showing a higher propensity to repurchase than Chinese consumers. Conclusions: Theoretical implications of the study contributed to understanding consumer behavior by confirming the impact of private label cues, elucidating their differential effects on repurchase intention, and integrating theoretical frameworks. Managerial implications underscored the significance of leveraging cues to enhance consumption value perceptions, tailoring marketing strategies to accommodate cultural nuances, and utilizing cues to bolster consumer repurchase intentions, ultimately enhancing distribution channel effectiveness.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.933-937
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• 2006

Energy is motive power that makes convenient society. But, our country's energy is depending on most import. Also, energy and environmental issue are important problem in community of nations. The purpose of this study is to analysis the energy consumption and environmental load of EHP and GHP in Medium and small-scaled office building. The annual energy consumption used to cooling and heating by EHP was 10 percent more than GHP. And annual energy cost of EHP was 33 percent more expensive than GHP. But, Compared to the annual $CO_2$ emission, EHP was 6 percent less than GHP. Therefore, equipment selection should be consider environmental load as well as energy consumption and cost.

• Journal of Korean Institute of Architectural Sustainable Environment and Building Systems
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• v.12 no.6
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• pp.669-679
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• 2018

Energy consumption savings in buildings should be reviewed in diverse areas such as air conditioning system and lighting responsible for cooling and heating, and energy management systems such as BAS (Building Automation System) and BEMS (Building Energy Management System) are introduced to improve energy consumption efficiency and to promote economic control of related facilities by integrated management of energy generated and consumption in buildings. The measured building of this study uses regenerative geothermal system. Measured values of heat pump and system COP were 4.7 and 4.2 respectively, and they were found to be higher 11.9% and 23.5% than rated values. As a result of analyzing the air conditioning and lighting energy from the first floor to the fourth floor performing the air conditioning, the second and third floors, which have a high frequency of use, are compared with the first and fourth floors 50% higher energy consumption ratio. On the other hand, the general heat storage system uses the nighttime power of the previous day to store heat and use it the next day. The total number of days of abnormal operation during the summer season is 61 days. The electricity cost corresponding to the abnormal operation is 1,840,641 KRW, and the normal operation using the nighttime power is 1,363,561 KRW, which is difference of 477,080 KRW, 35% increase in cost. We will utilize it as the main data of BEMS through analysis of winter operation characteristics as well as summer operation characteristics.