• Environmental and Resource Economics Review
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• v.31 no.4
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• pp.571-595
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• 2022

This study theoretically analyzes the cost allocation of replacement costs that occur when existing operators have to replace circuit breakers due to the entry of new generators. We adopt the sequential equal contributions rule as the cost allocation rule, which is widely used in cost allocation problems in cooperative game theory. We derive various cost allocation plans based on several criteria and examine to what extent each alternative meets various desirable axioms. According to the analysis, (i) the alternative that excludes the cost of the new operator, residual value, and network operator and (ii) the alternative that excludes the cost of the new operator, residual value, and includes network operator are relatively superior to other schemes. We also identify a realistic plan by taking into account practical factors and analyze its axiomatic characteristics.

• Journal of Korean Society of Steel Construction
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• v.17 no.2 s.75
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• pp.115-130
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• 2005

This paper presents the effects of indirect costs on Life-Cycle-Cost(LCC) effective optimum design of steel-box girder bridges. The LCC formulations considered in the LCC optimization of the bridges consist of initial cost and expected rehabilitation costs including repair/replacement costs, loss of contents or fatality and injury losses, and indirect costs such as road user costs and indirect socio-economic losses. To demonstrate the LCC-effectiveness for optimum design of the bridges, an actual steel box girder bridge having two continuous spans(2@50m=100m) is considered as a numerical example. And also, in this paper, various sensitivity analyses are performed to investigate the effects of indirect costs caused by traffic conditions such as number of detour route, number of lane on detour route, length of detour route, and traffic volumes on the LCC-effective optimum design. From the numerical investigations, it may be concluded that indirect costs caused by traffic network may sensitively influence on the LCC-effective optimum design of steel-box girder bridges. Therefore, it may be stated that the traffic conditions should be considered as one of the important items in the LCC-effective optimum design of the bridges.

• Membrane and Water Treatment
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• v.3 no.3
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• pp.141-149
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• 2012

The aeration provided in a Submerged Membrane Bioreactor (SMBR) improves membrane filtration by creating turbulence on the membrane surface and reducing membrane resistance. However, conventional hollow fiber membrane modules are generally packed in a vertical orientation which limits membrane scouring efficiency, especially when aeration is provided in the axial direction. In the present research, 3 innovative hollow-fiber membrane modules, each with a different membrane orientation, were developed to improve membrane scouring efficiency and enhance permeate flux. Pilot testing was performed to investigate the permeate flux versus time relationship over a 7-day period under different intermittent modes. The results indicated that the best module experienced an overall permeate flux decline of 3.3% after 7 days; the other two modules declined by 13.3% and 18.3%. The lower percentage of permeate flux decline indicated that permeate productivity could be sustained for a longer period of time. As a result, the operational costs associated with membrane cleaning and membrane replacement could be reduced over the lifespan of the module.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.216-219
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• 2008

As a future clean substitute energy, the Gas hydrate development projects are world widely carried out to prepare the shortage of petroleum and natural gas resources. The OIIP of gas hydrate is estimated approximately 10 Trillion LNG equivalent ton and it reaches almost the amount of 5 thousand years use for the world people. To develop the commercial production technology, several research projects like Malik and Alaska project have been carried by several advanced countries and teams, but nobody have succeeded it yet due to the technical problems and the high risks. The technologies developed up to now for the hydrate production are categorized to four methods, such as depressurization method, thermal recovery method, inhibitor injection method and replacement method. As these methods are highly related to the costs and the environmental problems, many other researches including the safety, environment and disaster prevention are actively fulfilled as well.

• Journal of Sensor Science and Technology
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• v.22 no.4
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• pp.292-296
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• 2013

The ultrasonic wind sensor that pass through the air, beating the delivery of ultrasonic wind speed increases or decreases by the physical characteristics of the wind speed and the direction of the sensor, the transmission and reception of ultrasonic time difference measured by a two-axis vector wind and wind speed measured by calculating a device that converts the digital signal is Anemometer and wind direction meteorological facilities management, management of the ship sail used for various purposes, including, but used the existing 3-cup (mechanical) anemometer wind rotor caused by mechanical wear parts replacement due to the short-term, the reliability of the product is low, parts replacement, and according to the characteristics caused the car, there is a problem in high maintenance costs. In addition, because the bearings use of the marine environment and the cryogenic environment was constrained. In this study, the excellent long-term reliability, using ultrasonic-type environment that is not constrained to produce wind anemometer located $90^{\circ}$ conformal road using four piezoelectric sensors were fabricated structures, the piezoelectric oscillator circuit produces a rash and receiving transmit and receive speeds the car through the two-axis vector calculation to measure wind velocity processor firmware programming, and its characteristics were tested.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.10
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• pp.87-97
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• 2020

In general, tires require various sensors and power supply devices, such as batteries, to obtain information such as pressure, temperature, acceleration, and the friction coefficient between the tire and the road in real time. However, these sensors have a size limitation because they are mounted on a tire, and their batteries have limited usability due to short replacement cycles, leading to additional replacement costs. Therefore, vibration energy harvesting technology, which converts the dynamic strain energy generated from the tire into electrical energy and then stores the energy in a power supply, is advantageous. In this study, the output voltage and power generated from piezoelectric elements are predicted through finite element analysis under static state and transient state conditions, taking into account the dynamic characteristics of tires. First, the tire and piezoelectric elements are created as a finite element model and then the natural frequency and mode shapes are identified through modal analysis. Next, in the static state, with the piezoelectric element attached to the inside of the tire, the voltage distribution at the contact surface between the tire and the road is examined. Lastly, in the transient state, with the tire rotating at the speeds of 30 km/h and 50 km/h, the output voltage and power characteristics of the piezoelectric elements attached to four locations inside the tire are evaluated.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.11
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• pp.1511-1519
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• 2013

This paper proposes the allocation method for capacitor-reactor banks in a distribution system with dispersed generators to reduce the installation costs, the maintenance costs and minimize the loss of electrical energy. The expected lifetime and maintenance period of devices with moving parts depends on the total number of operations, which affects the replacement and maintenance period for aging equipment under a limited budget. In this paper, the expected device lifetimes and the maintenance period are included in the formulation, and the optimal operation status of the devices is determined using a genetic algorithm. The optimal numbers and locations for capacitor-reactor banks are determined based on the optimal operation status. Simulation results in a 69-bus distribution system with the dispersed generator show that the proposed technique performs better than conventional methods.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.1
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• pp.44-49
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• 2015

Ceiling cooling and heating system that consider load arrangement and space in the ceiling needs to be developed. Therefore, experimental and economic changes were done to verify the performance of compact type VAV. The test results were as follow. 1) Noise test result, measuring approximately 50.4 dB~56.6 dB (before ceiling in landfill), had a better ceiling deadline than the current measure, about a 10 dB noise reduction, so that the office baseline (40~50 dB) noise was judged to be less than test. 2) For the static pressure test result, taking out an outside hydrostatic 25 mmAq, 24.8 mmAq was measured, respectively, at the point. 3) For the life-cycle cost analysis result, the initial investment cost, maintenance replacement costs, and maintenance costs increased 0.2%, but the energy savings ratio was 19.5% while the whole life cycle savings of 40 years LCC was reduced 11.9%.

• Journal of Multimedia Information System
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• v.3 no.3
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• pp.63-68
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• 2016

Environmental downtime produces a significant cost to organizations and makes them unable to do business because what happens in the data center affects everyone. In addition, the amount of electrical energy consumed by data centers increases with the amount of computing power installed. Installation of physical Information Technology and facilities related to environmental concerns, such as monitoring temperature, humidity, power, flood, smoke, air flow, and room entry, is the most proactive way to reduce the unnecessary costs of expensive hardware replacement or unplanned downtime and decrease energy consumed by servers. In this paper, we present remote system for monitoring datacenter implementing using open-source hardware platforms; Arduino, Raspberry Pi, and the Gobetwino. The sensed data displayed through Arduino are transferred using Gobetwino to the nearest host server such as temperature, humidity and distance every time an object hitting another object or a person coming in entrance. The raspberry Pi records the sensed data at the remote location. The objective of collecting temperature and humidity data allows monitoring of the server's health and getting alerts if things start to go wrong. When the temperature hits $50^{\circ}C$, the supervisor at remote headquarters would get a SMS, and then they would take appropriate actions to reduce electrical costs and preserve functionality of servers in data centers.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.3
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• pp.26-31
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• 2014

High temperature fuel cell system, such as molten carbonate fuel cells(MCFC) and solid oxide fuel cells(SOFC), are capable of operating at MW rated power output. The power output change of high temperature fuel cell imposes the thermal and mechanical stresses on the fuel cell stack. To minimize the thermal-mechanical stresses on the stack and increase the systems reliability, we should divide the power plant configuration to several banks. However, the improvement of reliability in fuel cell power plant system causes an increase of the investment cost, for example, replacement costs, labor costs, and so on. For this reason - the balance between investment and reliability improvement - many studies about the appropriate level of investment have been conducted. In this paper, we evaluate the cost for operation and installation, the benefit for electric energy and thermal energy sales, and the system reliability for several cases : these cases relate with the bank configuration.