• Design & Manufacturing
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• v.1 no.1
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• pp.7-11
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• 2007

The fabrication of precision optical components by deterministic CNC grinding is an area of great current interest. Replacement of the traditional, craftsman driven, optical fabrication process is essential to reduce costs and increase process flexibility and reliability. Moreover, CNC grinding is well suited to the fabrication of complex shapes such as aspheres, making it possible to design optical systems with fewer components and reduced weight. Current technology is capable of producing surfaces with less than 2 microns peak to valley error, 50 nm rms surface roughness, and less than 1 micron subsurface damage. Bound abrasive tools, in which the abrasive particles are fixed in a second (matrix) material, play an important part in achieving this performance. In this paper, the factors affecting the ultra-fine surface roughness and profile accuracy of machined surfaces of aspheric parts has been analyzed experimentally and theoretically and on ultra-precision aspheric grinding system and precise adjusting mechanism have been designed and manufactured. In the paper we report the results of experiments and modeling performed to examine the effects of machinability, occurring during grinding of optical surfaces, on the tool surface profile. Profiles of machined surface were measured by using SEM. In order to optimize grinding conditions of aspheric lens processing, we performed experiments by design of experiments.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.17 no.6
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• pp.1-15
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• 2014

A dredging on erosion control dam has been enforced without evaluation the factors that affect the dredging. In addition, there is the negative effect much more than positive effect by dredging on erosion control dam. Therefore, this study was carried out to develop evaluation indicators and to suggest fieldbook in order to determine whether sand deposits at erosion control dam should be dredged up or not. The most important six evaluation indicators that can decide to dredge up at erosion control dam were obtained from three round delphi technique and were selected in the following order: the current sand deposit ratio(0.339), existence of cultivated land and house downstream(0.276), the slope of streambed(0.162), the amount of movable soil and gravel(0.118), the history of any disasters(0.063), the basin area(0.043). The weighted score for each evaluation indicator were acquired from AHP analysis with respect to the degree of importance and then the modified weighted score for actual measurements were classified as three categories: large(2.53), medium(1.60) and small(1.01). Based on delphi technique, erosion control dam dredging evaluation fieldbook introduced the four evaluation indicators out of the total six evaluation indicators and two low effected evaluation indicators were excluded. This results showed that the values for reliability analysis and consistency ratio were acceptable.

• Science of Emotion and Sensibility
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• v.23 no.1
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• pp.69-78
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• 2020

This study compares and analyzes user experiences of intelligent personal assistant services based on the evaluation criteria of human-computer interaction to explore positive elements of user experiences and factors that could be improved. The research was conducted on Apple's Siri, Google's Google Associate, and Samsung's Bixby, which is presently the smartest personal assistant service on the market. The research method was to compare and analyze the concepts and characteristics of the current services through a literature review and by interviewing seven UI/UX design experts for the second 2 weeks using contextual inquiry. The interview reorganized Peter Morville's user experience honeycomb, reducing his seven usability principles down to five, asking questions about usability, convenience, visual attractiveness, reliability, and satisfaction. On the basis of the reconfigured usability principle, the assessment was conducted on the basis of the assessment timing and the system usability scale. This study is meaningful in that it analyzed the user experience of artificial intelligence personal assistant services both quantitatively and qualitatively.

• International Journal of Highway Engineering
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• v.14 no.6
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• pp.139-148
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• 2012

PURPOSES : The accuracy of travel time information is a key measure of effectiveness and reliability of advanced traveler information systems. This study aims at investigating drivers' perception on the acceptable level of information accuracy and their corresponding valuations. METHODS : A questionnaire survey was executed for collecting driver perception data to capture the expectation level of travel time information provided and their willingness to pay for the information. A Tobit model was adopted for exploring the relationship among the acceptable level, driver socioeconomic characteristics and travel attributes. Since drivers' willingness to pay for accurate travel time information can be different according to their travel lengths, a piecewise linear regression model was developed to capture the sensitivity of values of travel time information to travel length. RESULTS : The analysis results suggest that trip purpose and travel time are two dominant factors to determine drivers' acceptable level of travel time information. For business and short trips, drivers want more accurate information than for non-business and long trips. Drivers' willingness to pay for travel time information also varies depending on their incomes, trip purposes and travel lengths. The results also show that drivers' valuation of travel time information provided is sensitive to their travel length. For longer trips, drivers are less sensitive to travel time information and then put less value on the information provided. CONCLUSIONS : Censored nonlinear regression models are developed to estimate drivers' acceptable accuracy for travel time information and their valuation using questionnaire survey data. The findings on drivers perception to the required accuracy of travel time information and their corresponding willingness to pay can be used in the design and deployment of advanced traveler information system to improve its effectiveness and usefulness through high compliance.

• Journal of Welding and Joining
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• v.29 no.1
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• pp.99-106
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• 2011

Joint strength between a solder ball and a pad on a substrate is one of the major factors which have effects on electronic device reliability. The effort to improve solder joint strength via surface cleaning, heat treatment and solder composition change have been in progress. This paper will discuss the method of solder ball joint strength improvement using LF hydrogen radical cleaning treatment and focus on the effects of surface treatment condition on the solder ball shear strength and interfacial reactions. In the joint without radical cleaning, voids were observed at the interface. However, the specimens cleaned by hydrogen-radical didn't have voids at the interface regardless of cleaning time. The shear strength between the solder ball and the pad was increased over 120%(about 800gf) when compared to that without the radical treatment (680gf) under the same reflow condition. Especially, at the specimen treated for 5minutes, ball shear strength was considerably increased over 150%(1150gf). Through the observation of fracture surface and cross-section microstructure, the increase of joint strength resulted from the change of fracture mode, that is, from the solder ball fracture to IMC/Ni(P) interfacial fracture. The other cases like radical treated specimen for 1, 3, 7, 9min. showed IMC/solder interfacial fracture rather than fracture in the solder ball.

• Journal of Korean Society on Water Environment
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• v.30 no.6
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• pp.585-595
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• 2014

The temporal trends of the prioritized toxic water pollutants generated and discharged from the industrial facilities in the Geum-River basin, Korea were analyzed with the results of the nationwide Water Pollution Source Survey conducted in 2001 - 2012. The statistical results indicated rapid increase in the volume of raw toxic wastewaters whereas the amount of each toxic pollutant kept fluctuating for 12 years. Serious discrepancies in the survey data of the same type of industries demonstrated a low reliability of the survey result, which stemmed from several error factors. A unit-load for each type of industrial facility was devised to estimate the amount of prioritized toxic water pollutant based on the total volume of industrial wastewater generated from the same type of industrial facilities. The supplementary measures with an effective permit issuance policy and adding survey parameters of terminal wastewater treatment plants to use them as references to the Water Pollution Source Survey were suggested as means to minimize the errors associated with the false reports from the industries.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.2
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• pp.37-42
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• 2008

Defects of corrugated board were limiting factors to the corrugated industry's growth. On-line detecting systems of defects are beneficial to increase profits of the corrugated board companies by reducing base paper consumption, increasing process reliability, and increasing productivity. By replacing naked eye inspection of defects to a defects detecting system, continuous inspection without fatigue may guarantee final products quality. The system was developed, which was consisted of line scan CCD camera, lens, illuminating parts, high speed image processor, software, various input parts, and output parts. First installation location of the system was at before fluting process after base paper unwinding, and surface of liner board was inspected by the system. Second installation location was after fluting process and combining process for liner board. Production loss includes ragged appearance of edge, irregular flute shape, wrong combination of flute, score cracking, defects in base paper, and flute cracking. The production loss was analyzed before and after the system installation at a commercial domestic mill. The production loss ratio was defined as a production loss weight per total production weight. The production loss ratio before the installation was decreased a lot from 1.28%(during 3 months before installation) to 0.76%(during 12 months after the first installation) and to 0.25%(during 6 months after the second installation).

• Korean journal of food and cookery science
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• v.29 no.6
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• pp.709-715
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• 2013

The purposes of this study were to consider the influence of person-environment fit in the family restaurants on employees' stress. Based on total 274 samples obtained from empirical research from March 20 to April 10, 2013, self-administrated questionnaires were completed by patrons in metropolitan area and data were analysed by frequency, exploratory factor analysis, reliability analysis, correlation analysis, t-test, one-way ANOVA, and multi-regression analysis. Results of study were as follows: From the exploratory factor analysis of the variables, 4 factors, i.e. person-organization fit(3 variables), person-job fit(3 variables), person-supervisor fit(3 variables), and employees' stress(5 variables) were extracted. The results showed that employees' person-organization fit was significant differences according to gender(male $4.43{\pm}1.45$; female $4.83{\pm}1.34$; p<0.05). In terms of employees' person-supervisor fit was significant differences according to age(20' $3.08{\pm}0.99$, 30' $3.52{\pm}0.10$; 40' $3.71{\pm}1.07$; p<0.05). Also, the person-job fit(${\beta}$=-0.472; p<0.001), and person-supervisor fit(${\beta}$=-0.285; p<0.001) among the person-environment fit had a significant negative effect on employees' stress. Limitations and future research directions are also discussed.

• Journal of Arbitration Studies
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• v.21 no.2
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• pp.47-64
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• 2011

The China International Economic and Trade Arbitration Commission(CIETAC) released online arbitration rules which apply the resolution of disputes over electronic commerce transactions, as well as other economic and trade disputes in which the parties agree to do. The evidence submitted by the parties may be electronic evidence created, sent, received or stored by electronic, optical or magnetic means. Electronic evidence with a reliable electronic signature shall carry the same effect and probative force as a document with a hand-written signature. Where a case is tried in a tribunal, the arbitration tribunal shall conduct an online trial hearing using internet video conference or other electronic or computer communication means. Unless the parties have another agreement, summary procedure shall apply to cases where the amount in dispute exceeds RMB 100,000 but no more than RMB 1 million, or where the amount in dispute exceeds RMB 1 million and a party submits a written application for summary procedure after obtaining the written consent of the other party. Unless the parties have agreed otherwise, fast-track procedure shall apply to cases where the amount in dispute does not exceed RMB 100,000 or where the amount in dispute exceeds RMB 100,000 and a party submits a written application for fast-track procedure after obtaining the written consent of the other party. Notable features of the Online Rules are as follows; first, there is not detailed consideration for online arbitration. Second, communications between the parties and the tribunal are allowed only through the Secretariat. Third, elaborate provisions regarding the electronic submission and transmission of documents is provided for. Forth, various factors must be considered by the tribunal in deciding the evidence's reliability. Fifth, reasonable endeavours is levied on CIETAC to keep data communications secure and encrypted. Sixth, the tribunal has the right to investigate and collect relevant evidence. And finally different procedures are provided for in consideration of the various types of E-commerce.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.28 no.4
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• pp.197-212
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• 2017

Objectives: This study aims to supplement the limitations of the preliminary study and expand the use of the Child-Adolescent Functional Assessment Scale by providing standardized T-scores for measuring function in different areas, as well as guidelines for their interpretation. Methods: The Child-Adolescent Functional Assessment Scale and Korean-Child Behavior Checklist were administered to a total of 623 individuals, including 467 parents of emotionally and behaviorally disturbed elementary school students, 45 parents of emotionally and behaviorally disturbed middle school adolescents and 111 parents of elementary school students with developmental disorders, as well as to a control group consisting of 186 parents of mainstream elementary school children in the Seoul metropolitan area. Results: In contrast to the preliminary study, the emotional domain was disassociated into two factors, negative affect and emotion regulation, and the coefficient of determination for misconduct was increased significantly. Also, the overall reliability and validity of the Child-Adolescent Functional Assessment Scale were similar to those in the preliminary study, and the item structure was consistent. This study provides standardized T-scores of function in different areas based on the revised scale, and provides guidelines for their interpretation. Conclusion: The Child-Adolescent Functional Assessment Scale can assist the Child Global Assessment in Functioning in providing the information necessary for case management and treatment planning by comparing the impairment severity in each area of functioning, and also determining changes in behavior and function after treatment interventions. On the other hand, this scale has yet to clearly distinguish between rebellious behavior and misconduct. Further research is necessary to provide standards for more diverse age groups and for its utilization.