• Korean Journal of Environment and Ecology
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• v.28 no.1
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• pp.71-79
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• 2014

The goal of this study is to estimate economic benefit of restoring ecological stream of Hong Cheon river. The benefit is determined by estimating willingness-to-pay for the value of Hong Cheon river because it is a non-market good which is difficult to be measured in terms of monetary value. Specifically, the spike model, one of the contingent valuation methods, is used to distinguish respondents having zero willingness-to-pay for Hong Cheon river. The results show that a household located near the Hong Cheon river is willing to pay 3,300~4,628 Korean Won per year, while a household not located near the Hong Cheon river is willing to pay 1,308~2,929 Korean Won per year. Thus, total benefit of restoring ecological stream of Hong Cheon river is estimated as 97.6~216.3 billion Korean Won.

• Journal of the Korean Regional Science Association
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• v.31 no.3
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• pp.79-97
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• 2015

This paper attempts to quantify the economic value of the recreational benefits from the Jangheung dam. To this end, the contingent valuation (CV) survey was administrated to a sample of randomly selected 1,000 households from the national population. We used single-bounded model as a method of eliciting the willingness to pay (WTP) and applied a spike model to deal with zero WTP responses (72.5%) from the CV survey. The respondents were asked to state whether to pay a given amount through additional higher income tax once a year for next ten years. The results show that the annual recreational benefits of the Jangheung dam are estimated to be 1,348 won per household, which is statistically significant at the 1% level. Expanding the value to the national population gives us 24.9 billion won per year.

• Environmental and Resource Economics Review
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• v.22 no.2
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• pp.281-307
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• 2013

There has been some debates about zero willingness to pay in contingent valuation method research. Therefore, this paper tries to estimate and compare the results of various models to handle zero willingness to pay responses. For this purpose, we have employed parametric estimation such as the mixed model and the spike model, as well as non-parametric estimations. As a result, these models derived WTP estimate different from conventional model, but they also show some weakness. Therefore, in future research, more conservative estimate of the model should be to use rather than specific model.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.2
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• pp.461-468
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• 2010

This paper presents a simple digital LCD backlight inverter using a single-chip microcontroller. The proposed inverter reduces the ignition voltage and eliminates the current spikes and hence improves the ignition behavior of the cold cathode fluorescent lamp(CCFL). Thus it increases the CCFL's life span. This is achieved by implementing a digital dimming control algorithm, that contains the soft-starting algorithm, all on a single-chip microcontroller. The inverter utilizes the full-bridge resonant circuit topology. The design example along with a simple analysis for the inverter is shown, and the experimental results of the designed prototype results in close agreement with the theoretical analysis and explanation. The overall system's power efficiency is approximately 85%. Compared with conventional inverters, the ignition voltage is reduced by around 30% without any lamp current spike occurring during the dimming control operation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.6
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• pp.8-17
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• 2010

This paper proposes a novel LCD CCFL-backlight electronic ballast using the phase-shift full-bridge inverter. The proposed electronic ballast reduces the ignition voltage and eliminates current spikes using the new digital dimming control applied with soft-starting. Thus the electronic ballast improves ignition behavior of the CCFL and hence increases the CCFL's life span. For this, this paper analyzes the full-bridge inverter topology of the proposed electronic ballast and explains the new digital dimming control algorithm applied to the ballast, briefly. And this paper shows a design example of the prototype circuit and explains an implementation method of the digital dimming control which is implemented on a single-chip microcontroller with software. This was implemented as actual prototype electronic ballast, and its experimental results showed that the proposed electronic ballast operates correctly. The ignition voltage of the prototype in the digital dimming operation was reduced about 30[%] compared with the conventional electronic ballast and there were not any current spikes.

• Korean Journal of Applied Biomechanics
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• v.16 no.4
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• pp.125-134
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• 2006

The purpose of this study was to analyze the Biomechanical elements by looking at the differences on the motions of the right and left spikes of right-handed offense volleyball players, using 3D image analysis and force platform. For that purpose, spike motions of six male university volleyball players were recorded three times each using two 16mm high speed cameras and the speed of recording was set at 60 frames/sec. The coordinated raw data was leveled as 6Hz using low pass filtering method and the calculation of 3D coordinates was done by using a DLT (Direct Linear Transformation) method. Also KWON 3D program was used to analyze the variables. Through the experiments and research, the following results were found: That is, in case of the right spike, the required time from the toss to the impact, which affected the success rate of offense showed as longer and on the take-off, the exact timing to touch the ball was longer because the pace between right and left feet was wider, and also after the jump, the distance between the feet indicated shorter, than the left. In addition, the degree of somersault and horizontal adduction of shoulder joint was smaller and the degree of medial rotation of shoulder joint showed bigger than the left, so it indicated that it was not centered on the body, but by the arm with an axis of shoulder using a swing motion. After the impact, the speed of the ball indicated slower compared to the left spike.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.9 no.4
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• pp.309-317
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• 2015

In this paper, we proposed the standard test specification for safety and function of hiking stick for the elderly. We have concluded nine factors representing specification of hiking stick through analysis of hiking patents and research papers, products survey of business market, case studies for damaged hiking stick and expert surveys. To test the factors, we designed three different kinds of apparatus to examine twist resistance, stick and tip durability and stick straightness. The sample of hiking sticks purchased from market based on Naver sales ranking top to fifteenth. As a result, we concluded six-standard test specification based on eccentric load, adjustable parts load, hand strap load, basket load, tip load and pull load of hiking stick.

• Journal of Korea Water Resources Association
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• v.46 no.10
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• pp.989-995
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• 2013

This study attempts to estimate the benefits of environmentally-enhancing water ensuing from Sangkwan multi-purpose reservoir. To this end, we apply a survey technique, the contingent valuation (CV) method to elicit the public willingness to pay (WTP). Two CV surveys of randomly selected households were administrated to on-site and off-site areas. As it happens, a number of respondents reported zero WTPs for the environmentally- enhancing water. To deal with the zero WTPs, this study employs a spike model. The results show that average household's WTP for the environmentally-enhancing water ensuing from Sangkwan multi-purpose reservoir is estimated to be 1,393.7 won for on-site area and 2,237.7 won for off-site area per year. The benefits of environmentally-enhancing water ensuing from Sangkwan multi-purpose reservoir amount to about 38.3 billion won per year. Our findings are expected to contribute to determining an appropriate level of investment and making management policies with regard to the benefits of environmentally-enhancing water.

• Journal of Korea Water Resources Association
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• v.45 no.1
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• pp.29-37
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• 2012

This paper attempts to measure the economic benefits of tap water quality improvement using a specific case study of Ulsan, one of the large cities in Korea. To this end, we apply the contingent valuation (CV) method by employing a one-and-one-half bounded spike dichotomous choice question format. We surveyed a randomly selected sample of 400 households in Ulsan and asked respondents questions in person-toperson interviews about how they would willing to pay for the program. Respondents overall accepted the contingent market and were willing to contribute a significant amount (1,611 won), on average, per household per month. This willingness varies according to individual characteristics such as education level and income. The aggregate value of the program in Ulsan amounts to approximately 8 billion won per year.

• Journal of the Korea Society of Computer and Information
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• v.6 no.4
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• pp.94-99
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• 2001

Recently a lot of informations is interchanged among many users through the network such as Internet. In this situation. multimedia data transfer has some problems. that are jitter, the difference of delay in arriving packets, and loss of data due to the various delay between sender and receiver. The arriving data packets are not synchronized because of those problems. Especially, an efficient method is needed to revise the sudden large changes of the delay, called spike-like delay. which is occured in explosive growth of networking. We propose efficient synchronization algorithm which controls synchronization interval and adjusts to sudden changes in networks. The algorithm, a receiver-driven adaptive synchronization method, is to synchronize the arriving data packets against spike-like delay and decrease the loss of them. In addition, another method is proposed in this paper. The method uses the probabilistic features of delay distribution appearing in general network. It is evaluated for the loss of data packets and the delay times.