• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.4
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• pp.587-597
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• 2004

Over the past 20 years, great strides have been made in research regarding the mechanisms involved in the progression of carious lesions, but new equipment and research tools need to be developed to continue these advancements in caries research. Various methods have been applied to reduce the incidence of carious lesions, which have led to a significant decrease in the number of occlusal caries, but a concurrent increase in the proportion of proximal carious lesions. New diagnostic equipment has been developed to detect early stage carious lesions, and these have demonstrated excellent laboratory results and show promise in clinical applications. The research presented here examines the efficacy of the newly developed $DIFOTI^{TM}$ system in detecting proximal carious lesions compared to traditional intraoral exam and bitewing radiography, possible problems or deficiencies of using the system in clinic, possible improvements that can be made to the system, and the efficacy of detecting early, reversible carious lesions that can be remineralized by preventative fluoride applications. The subject pool consisted of 23 grammer school age patients just prior to entering the mixed dentition phase. Each patient was given a thorough oral examination, radiographic examination consisting of bitewing radiographs of the posterior teeth, and $DIFOTI^{TM}$ examination of the anterior and posterior teeth. Each examination was carried out two times by two examiners, and the data were statistically analyzed. The results are as follows: 1. The mean alpha value of reliability test of the visual oral examination was as follows; occlusal surface was 0.8470. mesial surface was 0.6430, distal surface was 0.5727. lingual surface was 0.2807 and distal surface was 0.2339. When the examination was limited to posterior teeth, the mean alpha value was as follows; occlusal surface was 0.8577, distal surface was 0.8211, lingual surface was 0.7728, buccal surface was 0.7152 and mesial surface was 0.6782. 2. The alpha value of reliability test of the radiographic analysis of carious lesions of the occlusal, mesial, and distal surfaces was 0.8500. 3. The alpha value of reliability test of the $DIFOTI^{TM}$ diagnostic analysis of carious lesions of the occlusal, buccal, lingual, mesial, and distal surfaces was determined to be 0.7917. 4. The $DIFOTI^{TM}$ diagnostic system was found to be the most accurate means of detecting occlusal, buccal, and lingual surface carious lesions (p<0.05), while mesial and distal proximal carious lesions were most accurately assessed using bitewing radiography (p<0.05).

• Journal of the Korean Society for Railway
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• v.20 no.1
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• pp.1-10
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• 2017

Brake squeal noise has been a challenging problems for a long time. It is very annoying to passengers and residents near tracks. Two methods have been applied to reduce or eliminate brake squeal noise. One is to improve frictional materials; the other is to optimize the topology and structures of brake pads. In this study, we developed two kinds of brake pads; one is a pad whose frictional material is different from the KTX brake pad friction material; the other is a flexible pad that has the same frictional material as that of the KTX brake pad, but a different structure. Squeal noise and friction coefficients were measured and analyzed using a full-scale brake dynamometer. It was found that the dynamometer test can simulate the squeal noise of KTX trains at stations. The squeal frequency of the KTX at 4500Hz was exactly reproduced; this value of 4500Hz was one of the natural frequencies of the KTX brake disc. It was also found that the squeal noise depended on the caliper pressure, initial disc temperature and braking speed. The average friction coefficient was 0.35~0.45. The new pad lowered the squeal noise by 17.3~21.6dB(A).

• The KIPS Transactions:PartB
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• v.16B no.4
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• pp.299-308
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• 2009

AAM(Active Appearance Model) is an algorithm to extract face feature points with statistical models of shape and texture information based on PCA(Principal Component Analysis). This method is widely used for face recognition, face modeling and expression recognition. However, the detection performance of AAM algorithm is sensitive to initial value and the AAM method has the problem that detection error is increased when an input image is quite different from training data. Especially, the algorithm shows high accuracy in case of closed lips but the detection error is increased in case of opened lips and deformed lips according to the facial expression of user. To solve these problems, we propose the improved AAM algorithm using lip feature points which is extracted based on a new lip detection algorithm. In this paper, we select a searching region based on the face feature points which are detected by AAM algorithm. And lip corner points are extracted by using Canny edge detection and histogram projection method in the selected searching region. Then, lip region is accurately detected by combining color and edge information of lip in the searching region which is adjusted based on the position of the detected lip corners. Based on that, the accuracy and processing speed of lip detection are improved. Experimental results showed that the RMS(Root Mean Square) error of the proposed method was reduced as much as 4.21 pixels compared to that only using AAM algorithm.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.5
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• pp.363-370
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• 2013

Small scale hydropower is one of most attractive and cost-effective energy technologies for installation within sewage treatment plants. This study was conducted to evaluate the potential of a semi-kaplan micro-hydropower (MHP) system for application to sewage treatment plants with high flow fluctuations and a low head. The semi-kaplan MHP is equipped with an adjustable runner blade, and is without a guide vane, so as to reduce the incidence of mechanical problems. A MHP rating 13.4 kWp with a semi-kaplan turbine has been considered for Kiheung Respia sewage treatment plant, and this installation is estimated to generate 86.8 MWh of electricity annually, which is enough to supply electricity to over 25 households, and equivalent to an annual reduction of 49 ton $CO_2$. The semi-kaplan turbine showed a 90.2% energy conversion efficiency at the design flow rate of 0.35 $m^3/s$ and net head of 4.7 m, and was adaptable to a wide range of flow fluctuations. Through the MHP operation, approximately 2.1% of total electricity demand of Kiheung Respia sewage treatment plant will be achievable. Based on financial analysis, an exploiting MHP is considered economically acceptable with an internal rate of return of 6.1%, net present value of 15,539,000 Korean Won, benefit-cost ratio of 1.08, and payback year of 15.5, respectively, if initial investment cost is 200,000,000 Korean Won.

• The Journal of the Korea Contents Association
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• v.16 no.10
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• pp.598-607
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• 2016

The purpose of this study is to suggest necessity of idea expression method suitable for people in our country and deduct Graphic Ideation method by grasping problems of existing idea expression method. The idea expression method (association stimulating method, conceptual shifting method, information combination method) used by many graphic designers is effective in suggesting initial keyword, but has difficulty in the course of deducting the concept. Though deduction of core keyword is important to develop as a concept, the course of separation, combination in keyword connection play an important role, and most of idea expression methods are unavailable for suggesting concrete method for the course. Also as most of idea expression methods were developed and delivered in English-speaking world, it is suitable in English-speaking world culture which has thinking focused on words, but people in our country, which have thinking focusing on narration, cannot consider difference in language thinking due to limitation in idea for each stage. This study deducted idea expression method suitable for emotion of people in our country by proving the value of this idea expression method with style of suggesting and demonstrating 4 hypotheses in order to make the course for easy connection, separation, combination of keyword deducted by existing idea expression method, as well as suggesting idea expression method design based on these hypotheses. This idea expression method used rhetoric so that it is suitable for people our country who are strong for narration expression.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.4
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• pp.25-32
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• 2010

High performance shotcrete has been recently researched partly as a result of high consensus on high strength and durability. However, they are very initial step compared from the advanced countries. For instance, they has been mainly on high strength or durability without any consideration on pumpability and shootability which are very crucial on workability. The purpose of this dissertation was to make a high performance wet-mix shotcrete (high workability) which would solve the general problems of wet-mix process in Korea. For this, the main experimental variables were selected to be silica fume(0.0, 4.5, 9%), air entrained agent(0.0, 0.005%). Rheology with IBB rheometer was measured for evaluating pumpability and shootability as well as pump pressure, rebound rate and build-up thickness. The conclusions from a series of experiments were as follow: The results of analyzing the effects of AE agent and silica fume on rheology indicated that AE agent reduced both of flow resistance(G) and torque viscosity(H) and silica fume increased flow resistance (G) and reduced torque viscosity(H). An increase in the value of torque viscosity(H) produces an increase in the requried pumping pressure. These result indicated that the reduction of torque would work better at improving pumpability. And an increase flow resistance(G) improved shootability(increase build-up thickness and reduce rebound).

• The Journal of Engineering Geology
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• v.5 no.2
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• pp.193-200
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• 1995

It has been well known that the alkali-aggregate reaction between the aggregates and cement paste is one of the reasons of a concrete siructre expansion. Because of a serious demage on the concrete stnicture from the expansion, in many countries, the safety of the materials is checked in laboratory by mortar-bar test and the upper limit of expansion in length is 0.1%. The prescriptions are presented in the ASTM C227 and 490 of U.S. which has been international currency and in the KS Handbook F2503, F2546 and L5107 of Korea published by Korean Standards Association. Both of the prescriptions are almost same in their contents. Actually, in the process of preparing and measuring the mortar-bar according to the prescription mentioned above, it seems that there are no problems for its own purpose but a few points are found to be improved upon the methods to increase the accuracy for laboratory work as follows. 1. The prescription of blending ratio(aggregate, cement and water) should be noted by volume not by weight. 2. It is unreasonable to measure the initial length of mortar bars after 24$\pm$2 hours at once regardless the kind of aggregates. 3. It may bring about errors in calculating the expansion ratio under the condition of the denominator value fixed as 254mm. 4. The measuring methods of specific gravity are selected according to the purposes but the pure specific gravity displays the highest accuracy among them.

• Corrosion Science and Technology
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• v.9 no.6
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• pp.276-280
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• 2010

Copper(Cu) as an interconnecting metal layer can replace aluminum (Al) in IC fabrication since Cu has low electrical resistivity, showing high immunity to electromigration compared to Al. However, it is very difficult for copper to be patterned by the dry etching processes. The chemical mechanical polishing (CMP) process has been introduced and widely used as the mainstream patterning technique for Cu in the fabrication of deep submicron integrated circuits in light of its capability to reduce surface roughness. But this process leaves a large amount of residues on the wafer surface, which must be removed by the post-CMP cleaning processes. Copper corrosion is one of the critical issues for the copper metallization process. Thus, in order to understand the copper corrosion problems in post-CMP cleaning solutions and study the effects of DC biases and post-CMP cleaning solution concentrations on the Cu film, a constant voltage was supplied at various concentrations, and then the output currents were measured and recorded with time. Most of the cases, the current was steadily decreased (i.e. resistance was increased by the oxidation). In the lowest concentration case only, the current was steadily increased with the scarce fluctuations. The higher the constant supplied DC voltage values, the higher the initial output current and the saturated current values. However the time to be taken for it to be saturated was almost the same for all the DC supplied voltage values. It was indicated that the oxide formation was not dependent on the supplied voltage values and 1 V was more than enough to form the oxide. With applied voltages lower than 3 V combined with any concentration, the perforation through the oxide film rarely took place due to the insufficient driving force (voltage) and the copper oxidation ceased. However, with the voltage higher than 3 V, the copper ions were started to diffuse out through the oxide film and thus made pores to be formed on the oxide surface, causing the current to increase and a part of the exposed copper film inside the pores gets back to be oxidized and the rest of it was remained without any further oxidation, causing the current back to decrease a little bit. With increasing the applied DC bias value, the shorter time to be taken for copper ions to be diffused out through the copper oxide film. From the discussions above, it could be concluded that the oxide film was formed and grown by the copper ion diffusion first and then the reaction with any oxidant in the post-CMP cleaning solution.

• Journal of Family Resource Management and Policy Review
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• v.25 no.2
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• pp.13-24
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• 2021

The purpose of this study was to prepare basic data to set the support direction for low-income households in a socioeconomic crisis situation. The study examined the effect of socioeconomic deprivation experience on the longitudinal changes in family conflict and family relationship satisfaction of low-income households. Using five-year data from the 10th to 14th sessions of the Korean Welfare Panel, we examined the longitudinal changes in family conflict and family relationship satisfaction, and the effect of socioeconomic deprivation experience from the reponses of 803 low-income households. We found that the family conflict of low-income households decreased to a weak level with the change of time, and the rate of change in family relationship satisfaction was not meaningful. In the case of families who experienced early socioeconomic deprivation, their initial value of family conflict was higher than that of inexperienced households, and the rate of change was not significant. The results of this study show that when low-income households experience socioeconomic deprivation, they feel psychological pressure and an increase in family anxiety, resulting in high family conflict and low family relationship satisfaction. On the basis of the study results, we recommend extending economic and social assistance to low-income households in the current socioeconomic crisis. The state is also encouraged to help families manage conflicts on their own and resolve problems.

• Korean Journal of Forensic Psychology
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• v.11 no.3
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• pp.329-347
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• 2020

When a person suggests an estimate under uncertainty, (s)he tend to rely on the information and number provided in advance. As a result, their final estimate would be assimilated to the initial value. This phenomenon is called "anchoring effect". The present research examined anchoring effects observed in law courts. Sentencing decision of jurors can be influenced by the sentence demanded by the prosecutor. Specifically, this study demonstrated the condition in which anchoring effect would be stronger and practical solutions for lowering anchoring effect. Study 1 demonstrated whether gravity of criminal cases and levels of anchor influenced anchoring effects. As expected, anchoring effect was stronger in a heavier criminal case than in a lighter one. When a low anchor was provided in a lighter case, anchoring effect was stronger compared to when a high anchor was provided. Study 2 examined how emotion affects anchoring effects. The results showed that anchoring effect appeared to be significantly stronger with feelings of anger than of sadness. Study 3 examined the solution for reducing anchoring effects in a court. When activation of selective-accessibility model was prevented, anchoring effects significantly decreased. These results can help solve the problems about juror judgmental bias and contribute to the development of Korean jury trial.