• 상하수도학회지
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• 제13권2호
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• pp.82-88
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• 1999

This study was to evaluate disinfection efficiency of chlorine and chloramine as secondary disinfectants in the distribution systems. Indicator organism, HPC in the suspended and attached were measured for copper, galvanized steel, PVC, and carbon steel pipes. For suspended microorganism, the PVC pipe was markedly dense among the assessed pipe materials. The attached microorganism was markedly equivalent roughness of pipe materials. In copper and galvanized pipes, chloramine was more effective that free chlorine to disinfect suspended microorganism in the contact time of 2 hours. The contact time for the 99% inactivation of suspended microorganism by chloramine was longer than that of free chlorine. Regardless of pipe materials, chloramine was effective on both disinfection efficiency and 99% inactivation time for attached microorganism. In conclusion, chloramine which is good disinfectant for long contact time was recommended as secondary disinfectant in distribution system.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 춘계종합학술대회
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• pp.197-200
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• 2001

최근의 확산대역 통신 방식에 사용되는 주파수 합성기는 주파수 스위칭 시간이 중요한 요소가 되고 있다. FH-SS(Frequency Hopping Spread Spectrum) 송수신기에서 고속 주파수 합성기 설계는 채널 효율을 높이기 위해 매우 중요하다. 본 논문에서는 기존 PLL방식에 직접 접근 주파수 합성 (DDS) 방식을 응용하여 1 $\mu\textrm{s}$ 이하의 스위칭 시간을 갖는 고속 주파수 합성기를 설계하고, 이를 2.4GHz 대리의FH-SS 송수신기에 적용하여 시뮬레이션 결과 20% 이상의 채널 효율 개선 효과를 얻었다.

• 한국재료학회지
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• 제16권2호
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• pp.75-79
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• 2006

The effect of ozone and/or ultrasound treatments on the efficiency of slurry removal in post sliced cleaning (PSC) of silicon ingot was studied. Efficiency of slurry removal was evaluated as functions of time, temperature and surfactant with DOE (Design of Experiment) method. Residual slurries were observed on the wafer surface in case of cleaning by ozone or ultrasound separately. However, a clean wafer surface was appeared when cleaned with ozone and ultrasound simultaneously. It has found that cleaning time was the main effect among temperature, time and surfactant. Elevated temperature, addition of surfactant and high ozone concentration helped to accelerate efficient removal of slurry. The improvement of removal efficiency seems to be related to the formation of more active OH radicals. The highly cleaned surface was achieved at 10 wt% ozone, 1 min and 10 vol% surfactant with ultrasound. Application of ozone and ultrasound might be a useful method for PSC process in wafer cleaning.

• International Journal of Contents
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• 제13권4호
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• pp.39-46
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• 2017

Due to resource constraints, most of Android application developers need to address potential performance problems during application development and maintenance. The coding styles and patterns of Android programming could often affect the execution time and energy efficiency which are utilized by the Android applications. Thus, it is necessary for application developers to apply performance-enhancing programming practices for mobile application development. This paper introduces performance-enhancing best practices for Android programming, and further, it evaluates the impact of these practices on the CPU time of the application. The original version with the performance-worsening code has been refactored to become an efficient version without changing its functionality. To demonstrate the efficiency of the proposed approach, each coding pattern was evaluated by measuring the CPU time under the controlled runtime environment. Furthermore, the Android applications were evaluated and compared via the CPU time of the original version, with that of the refactored version. These experimental results indicate that, by -using the proposed programming practices, the Android developer can develop performance-efficient mobile applications.

• Journal of Information Processing Systems
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• 제20권3호
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• pp.307-316
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• 2024

In the realm of large-scale identification deployments, the EPCglobal Class-1 Generation-2 (Gen2) standard serves as a cornerstone, facilitating rapid processing of numerous passive RFID tags. The Q-Algorithm has garnered considerable attention for its potential to markedly enhance the efficiency of Gen2-based RFID systems with minimal adjustments. This paper introduces a groundbreaking iteration of the Q-Algorithm, termed Time-Efficient Q-Algorithm (SwiftQ), specifically designed to push the boundaries of time efficiency within Gen2-based RFID systems. Through exhaustive simulations, our study substantiates that SwiftQ outperforms existing algorithms by a significant margin, demonstrating exceptional expediency that positions it as a formidable contender in the landscape of large-scale identification environments. By prioritizing time efficiency, SwiftQ offers a promising solution to meet the escalating demands of contemporary Internet of Things applications, underscoring its potential to catalyze advancements in RFID technology for diverse industrial and logistical contexts.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2007년도 추계학술대회 및 정기총회
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• pp.141-144
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• 2007

This research aims to propose model for measuring the efficiency of R&D organizations by using Data Envelopment Analysis. In existing research about using Data Envelopment Analysis, the types of R&D organizations have not been clarified and the difference between analysis time from measurement time is usually $4{\sim}5$ years. This research divides R&D organizations into three types and provides proper methods for measuring the efficiency of each R&D organizations.

• 농업과학연구
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• 제37권3호
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• pp.509-514
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• 2010

The purpose of this study is to analyze the technical efficiency and its determinants for Korean Apiculture farming by using from door to door and e-mail inquiry data. The analysis was implemented through the Cobb-Douglas stochastic frontier production function (SFPF) model including the technical inefficiency effect model for cross-sectional data. To measure the SFPF model, honey production was used for a dependent variable, and for input variables labor cost, preventive cost, material cost, feeding cost, depreciation cost were used. Farmer's age, farmer's career, farming scale, full-time or half-time firm and movement or fixed firm variables were used to measure the inefficiency effect model. The average technical efficiency on apiculture farming in Korea is estimated to be 0.8112. It means that there were technical inefficiency of about 18.88% in Korea apiculture farming. In this study there are some suggestions which could increase the technical efficiency of Korean apiculture farming.

• 한국공작기계학회논문집
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• 제15권3호
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• pp.97-103
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• 2006

The development of a heat exchanger production model based on the microlamination technology and it's economic efficiency is addressed. A microchannel production model is proposed for the high-volume production. The microlamination system is made up of lamina patterning, laminae sorting and laminae bonding. A cost estimation model is developed based on the hewn cycle time and capital equipment costs. An economic efficiency analysis is performed to determine the cost drivers under the different market and product scenarios. The result of the economic efficiency analysis indicated that the device size and the production rate have a great effect on the overall manufacturing cost of microlamination devices. And it can be concluded that the microlamination should focus on bonding larger laminae and reducing both cycle time and warpage.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.481.1-481.1
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• 2014

Dye-sensitized solar cell (DSSC) has been extensively investigated as the next generation energy source. Despite attractive features of simple fabrication process and its economical efficiency, there are some problems such as low efficiency and low long-term stability. Many groups have attempted the proposed way to improve the cell efficiency and long-term stability such as low recombination rate between $TiO_2$ surface and electrolyte, the development of new dye molecules capable of light adsorption as broadly as possible, the fabrication of a solid-state DSSC by replacing the liquid electrolyte, and protective coating on glass. In this work, we confirmed new dye-coating conditions to maximize the dye adsorption between the dye and $TiO_2$ nanoparticle surface. The experiment results coating conditions with the coating temperature of $70^{\circ}C$, the dye concentration of 10 mM and the coating time of 3 min. Conditions have two times, three times cycle the experiment in progress efficiency rises.

• 설비공학논문집
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• 제12권10호
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• pp.908-916
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• 2000

In this paper, the characteristics of moisture ventilation in the lithium ion battery manufacturing dry room are studied numerically using standard $k-\varepsilon$ turbulence model. Both the steady-state and the unsteady behaviors of moisture ventilation are analyzed by considering local and uniform moisture generation. In order to evaluate the characteristics of moisture ventilation, three scales of ventilation efficiency and characteristic ventilation time are presented from the numerical results. It was shown that moisture distribution was dependent strongly on the flow field. The characteristics of moisture ventilation were improved by 20% and 40% in terms of the 1st scale of ventilation efficiency (SVE1) and the 2nd scale of ventilation efficiency (SVE2), respectively, through the modifications of design variables such as the addition of inlets, outlets and partition. A significant improvement in the characteristic ventilation time and the moisture exhaust efficiency was also made by these modifications.