• 전기의세계
• /
• v.22 no.6
• /
• pp.33-51
• /
• 1973

To lower the earth resistance shall be one of the most effective method for the prevention of lightening damage on power transmission line. In this report, in order to investigate various characteristic necessary to lowering the earth resistance, the following experiments have been made at 154KV U1San-PoHang T/L, 154KV YoSu-SoonChun T/L and so on. 1. Measurement of Earth specific resistance, 2. Efficiency of Earthing of concrete foundation for steel structure., 3. Efficiency of Earthing with counter poise., 4. Compound impulse test with foundation of steel structure and counter poise. With the above investigate a guidance have been prepared for the effective work-performance of steel structure.

• Journal of Smart Tourism
• /
• v.1 no.2
• /
• pp.13-18
• /
• 2021

Hotels have recently started to implement enterprise information systems to measure and report sustainability indicators in a smart manner. However, a complex ownership structure in a hotel chain prevents full smart systems adoption at the individual property level. This study explores how a smart sustainability performance measurement system (SPMS) for waste management adoption correlates with customer ratings, customer reviews, operational efficiency scores, and between franchised and corporate-managed properties. We derive insights from the secondary data constructed from multiple sources for a large multinational hotel chain hotel. The findings suggest that hotels that adopt SPMS have better operational efficiency scores and more customer reviews. Within the hotels that adopted SPMS, corporate-managed hotels have a lower level of ratings than franchised hotels, but they have higher operational efficiency scores and more reviews. We discuss research implications for the concept of smart tourism and hotel management literature and managerial implications.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.17 no.5
• /
• pp.416-422
• /
• 2012

This paper proposes a low power-loss current measurement using a resistor and bypass switch. Conventional current sensing method using a resistor has a disadvantage of power loss which degrades the efficiency of the entire systems. On the other hand, proposed measurement technique operating with bypass-switch connected in parallel with sensing resistor can reduce power loss significantly the current sensor. The propose measurement works for discrete-time sampling of current sensing. Even while the analog-digital conversion does not occur at the controller, the sensing voltage across the sensor still causes ohmic conduction loss without information delivery. Hence, the bypass switch bypasses the sensing current with a small amount of power loss. In this paper, a 90[W] prototype hardware has been implemented for photovoltaic MPPT experimental verification of the proposed low power-loss current measurement technique. From the results, it can be seen that PV power observation is successfully done with the proposed method.

• 한국신재생에너지학회:학술대회논문집
• /
• 2007.06a
• /
• pp.617-620
• /
• 2007

The performance evaluation of the Samcheonpo small-hydropower plant constructed on the October 25th,2006, was carried out focused on the turbine and generator efficiency analysis by using the measurement data. The unreasonable and unrealistic efficiency results are occurred in some periods because of the data variability, uncertainty, and measurement errors and mistakes. Whereas, the big mismatch is the tidal elevation predicted in the design processes. The difference between the measured and estimated tidal elevation is obvious during the low water period. It should be considered and checked in depth on the efficiency analysis of the planned and constructing small-hydro power plants in other coastal areas.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.36 no.4 s.107
• /
• pp.67-76
• /
• 2004

Because paper industry spends lots amount of water, the recycling of water is very important in economical as well as environmental aspects. In order to optimize the process water recycling system, the efficiency of unit operation for water circulation, such as save-all system, CDS and settling tank, plays an important role in. In this study, the sedimentation efficiency of process water was evaluated by SS measurement with the different amounts of flocculent addition. 3 different kinds of process water were collected from fine paper mill, and applied in laboratory sedimentation equipment for the measurement of settling efficiency of SS materials. The addition amounts of alum and PAC were resulted in optimum efficiency of sediments in the condition of 100 ppm of alum and 500 ppm of PAC respectively. In the comparison of sedimentation efficiency between alum and PAC, alum showed more economical and efficient results. The SS of spill water and the particle size of suspended materials treated by alum flocculents were below 50 ppm and about 1 $\mu$m. It would be considered that the spill water can be substituted to superclear water grade.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2023.05a
• /
• pp.118-120
• /
• 2023

Increasing port competition driven by the containerisation has motivated ports and terminals to focus on their performance to efficiently utilise the available resources and to make strategic decisions in port development and expansion. With both inter-port andintra-port competition increasing in the port of Colombo, this study aims to measure the efficiency of the container terminals in Colombo comparing to terminals in the port of Busan using the DEA window analysis to determine their operational efficiency and to provide suggestions for future port development activities. Multiple window analyses were conducted using CCR and BCC models with different orientations and window lengths to compare the efficiencies of 11 DMUs in both ports during the period from 2015-2019 to measure the efficiencies prior to the COVID-19 pandemic. Results revealed the largest terminal operator, PNC in Busan, to be the most efficient overall, while the second highest efficiency was recorded by one of the smallest terminal operators, SAGT in Colombo, among the sample. Although use of DEA in port performance measurement has been popular for many years, efficiency measurements in the port of Colombo, the main hub port in the South Asian region, has not been comprehensively studied so far.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.10 no.8
• /
• pp.945-952
• /
• 2015

Power amplification device which is matched to $50{\Omega}$ in order to achieve a high efficiency of a power amplifier using a GaN power amplification device, since there is a limit of application frequency bands, output power, efficiency characteristics selection, in this study based on the measurement data through the source/load-pull test, high output power and to extract quantitative input and output impedance that matches the design objectives of high output power, high efficiency, an implementation of the high efficiency power amplifier. Implemented power amplifier is shows 25watt(44dBm), PAE of 66-76% characteristics in the frequency band of 2.7-3.1 GHz.

• Journal of Advanced Marine Engineering and Technology
• /
• v.41 no.4
• /
• pp.362-367
• /
• 2017

This study was conducted to compare the particulate removal efficiency of the developed diesel particulate filter using various measurement methods in a high-speed marine diesel engine. A four-stroke mechanical marine diesel engine is used for the test, which has a maximum output of 403 kW and is coupled to an AC dynamometer to control engine speed and load. The test was conducted based on four steady-state engine operating conditions of E3 engine test cycle for the measurement of PM and soot removal efficiency using partial dilution method considered as gravimetric method and filter smoke number method as light absorption method, respectively. As a result of the removal efficiency measurement according to the application of diesel particulate filter, particulate matter was reduced from 76% to 91% and the soot was reduced by more than 90% while meeting the permissible engine back pressure. From these results, the applicability of diesel particulate filter adopted in high-speed marine diesel engines could be confirmed. In addition, based on the result that the particulate removal efficiency varies with different measurement methods, the necessity of unification of these methods could be identified.

• Nuclear Engineering and Technology
• /
• v.53 no.2
• /
• pp.695-698
• /
• 2021

Efficiency calibration is a fundamental procedure in gamma spectrometric measurement. Experimental technique for efficiency calibration transfer in gamma spectrometer along different geometries and volumes has been developed and validated in this work. The developed technique offers simple and easy procedures to overcome several problems encountered in efficiency calibration of gamma spectrometer such as rate-related correction and different sample volumes. The validation shows that application of the developed technique has a precision of 95%.

• Journal of Radiation Protection and Research
• /
• v.26 no.4
• /
• pp.393-398
• /
• 2001

The non-combustible RI wastes disposed of in hospital every year emit ${\gamma}$-ray or ${\beta}$-ray but their activities are very low to the extent of background. Development of more simple methods is needed because the conventional detection methods are so ineffective and complex. In this study, to solve this problem, detection method using efficiency curve for ${\gamma}$-ray emitting radioactive wastes measurement is proposed and experimental detection efficiency equation is also determined through HPGe's standard specimen measurement. For ${\beta}$-emitting radioisotopes detection, new measurement method using detection efficiency estimated by Monte Carlo simulation and SBD measurements is also proposed. According to the results of this paper, the unknown activity of low-level radioactive wastes without LSC requiring the preparation of standard sample and measurement for standard source detection efficiency could be determined efficiently and simply about ${\pm}17%$ in errors by using the theoretical detection efficiency and the SBD measurement result.