• 한국가시화정보학회:학술대회논문집
• /
• 2004.12a
• /
• pp.125-134
• /
• 2004

The improvement of artificial respiration method has brought about the decrease in mortality of pulmonary diseases patients. Various respiratory curative methods, inclusive of HFOV (High Frequency Oscillatory Ventilation), have been developed for more effectual and less harmful management of acute respiratory failure. However, the mechanism of gas transfer and diffusion in a bronchiole has not yet been clarified in detail. As a first approach to the problem, we measured oscillatory flows in a Y-shaped micro-channels as bronchiole model by micro Particle Image Velocimetry(micro PIV). In order to establish the fundamental technique of PIV measurements on oscillatory air flow in a micro-channel, we used about 500-nm-diameter incense smoke particles, a diode laser, a high speed camera including an objective lens, and a HFOV, which is effective technique for medical care of pulmonary disease patients, especially, infants. The bronchiole model size is that parent tube is $500\{mu}m$ width and $500\{mu}m$ depth, and daughter tubes are $450\{mu}m$ width and $500\{mu}m$ depth. From this study made on the phenomenon of fluid in micro size bronchus branch of a lung, we succeeded to get time series velocity distribution in a micro scale bronchial mode. The experimental results of velocity distribution changing with time obtained by micro PIV can give fundamental knowledge on oscillatory airflow in micro-channel.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.16 no.5 s.110
• /
• pp.514-520
• /
• 2006

In this study, the performance of a digital pile rebounding and penetration monitoring system (DPRMS) is evaluated and the measurement precision of the DPRMS is improved. The DPRMS is a high speed line-scanning camera system to measure the rebound and penetration of a pile in a construction work. A main problem in the DPRMS is a measurement error, which is caused by a shock or vibration due to a hammer impact. The measurement error is investigated by analyzing vibration signals of the DPRMS during the impact. Moreover, the frequency response functions of the DPRMS are also analyzed. As a result, it is found that the tripod height has an influence on the DPRMS performance and a shorter tripod is better. One more founding in this study is that the DPRMS should be placed with a appropriate distance from a pile for improving the measurement precision.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2004.11a
• /
• pp.325-333
• /
• 2004

Since 1995, One of the NGIS(National Geographic Information System) projects, the underground utilities project has been finished in 2003. The 19 cities in korea for this project will use underground utilities management system using underground utilities database focusing on water and sewage system. However, special expert, technical and experience problem in computer environment has not been had in working department for water and sewage management and maintenance for each local government. The management and maintenance of underground utilities database by manual method is getting lowered a data quality of underground utilities database because of the data omitting, error in writing and securing of the lasted database. Therefore, in this study, Application test for field workers using a mobile tool and environment analysis of wireless communication in Korea and application test of GPS receiver for mobile tools had been processed and made a mobile working environment. The efficient management and maintenance method for underground utilities database has been developed an off- line method for modification and update of database about general work which has a high working frequency because of the limitation of wireless communication environment Also, the emergency working has been applied for on-line method.

• Transactions of the Society of Information Storage Systems
• /
• v.1 no.2
• /
• pp.161-168
• /
• 2005

This paper optimizes the optical flying head(OFH) suspension using the integrated optimization frame, which automatically integrates the analysis with the optimization and effectively implements the repetitive works between them. The problem formulation for the optimization is suggested to improve the dynamic compliance of OFH and to shift the resonant frequencies caused tracking errors to high frequency domain. Furthermore, the minimization of the effective suspension mass that leads to decrease the so-called 'lift-off' as the disk-head separation acceleration divided by the suspension load is taken into consideration. In particular, this study is carried out the optimal design considering the process of modes tracking through the entire optimization processes. The advanced suspension that reduces the effective mass of the suspension and increases the resonant frequencies of sway and $2^{nd}$ torsion over 10kHz is achieved by using the integrated optimization frame.

• Journal of Korean society of Dental Hygiene
• /
• v.20 no.4
• /
• pp.479-490
• /
• 2020

Objectives: The purpose of this study was to investigate the actual condition of bullying in the workplace by dental hygienists and to determine whether workplace bullying affects job performance. Methods: Data were collected from 308 clinical dental hygienists working in dental medical institutions located in the whole country. Frequency analysis, descriptive statistics, t-test, and ANOVA were performed using SPSS 23.0 for analysis. Results: First, the main targets of bullying in the workplace were senior dental hygienists (53.6%) and dentists (24.7%). Second, the number of turnovers was a significant influence on bullying and job performance according to general characteristics. Finally, the 'improper work environment' among the subfactors of workplace bullying had a negative effect on 'job performance' (p<0.001). Conclusions: Based on the results of the study, we reviewed the actual condition of bullying in the workplace and whether bullying in the workplace affects job performance in the workforce problem of dental hygienists. In this regard, the importance of prevention of bullying in the workplace was discussed.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.3 no.6
• /
• pp.96-111
• /
• 1995

A bellows is a component installed in the automobile exhaust system to reduce the impact from an engine. It's stiffness has a great influence on the natural frequency of the system. Therefore, it must be designed to keep the specified stiffness that requires in the system. This study present the finite element analysis of U-typed bellows using a curved conical frustum element and the shape optimal design with specified stiffness. The finite element analysis is verified by comparing with the experimental results. In the shape optimal design, the weight is considered as the cost function. The specified stiffness from the system design is transformed to equality constraints. The formulation has inequality constraints imposed on the fatigue limit, the natural frequencies, the buckling load and the manufacturing conditions. A procedure for shape optimization adopts a thickness, a corrugation radius, and a length of annular plate as optimal design variables. The external loading conditions include the axial and lateral loads with a boundary condition fixed at an end of the bellows. The recursive quadratic programming algorithm is selected to solve the problem. The result are compared with the existing bellows, and the characteristics of the bellows is investigated through the optimal design process. The optimized shape of the bellows are expected to give quite a good guideline to the practical design.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.9 no.5
• /
• pp.1642-1661
• /
• 2015

Wireless mesh networks are a special type of broadcast networks which cover the qualifications of both ad-hoc as well as infrastructure mode networks. These networks offer connectivity to the last mile through hop to hop communication and by comparatively reducing the cost of infrastructure in terms of wire and hardware. Channel assignment has always been the focused area for such networks specifically when using non-overlapping channels and sharing radio frequency spectrum while using multiple radios. It has always been a challenge for mesh network on impartial utilization of the resources (channels), with the increase in users. The rational utilization of multiple channels and multiple radios, not only increases the overall throughput, capacity and scalability, but also creates significant complexities for channel assignment methods. For a better understanding of research challenges, this paper discusses heuristic methods, measurements and channel utilization applications and also examines various researches that yield to overcome this problem. Finally, we highlight prospective directions of research.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.6 no.6
• /
• pp.1627-1648
• /
• 2012

We propose an adaptive method for detecting plagiarized pairs from a large set of source code. This method is adaptive in that it uses an adaptive algorithm and it provides an adaptive threshold for determining plagiarism. Conventional algorithms are based on greedy string tiling or on local alignments of two code strings. However, most of them are not adaptive; they do not consider the characteristics of the program set, thereby causing a problem for a program set in which all the programs are inherently similar. We propose adaptive local alignment-a variant of local alignment that uses an adaptive similarity matrix. Each entry of this matrix is the logarithm of the probabilities of the keywords based on their frequency in a given program set. We also propose an adaptive threshold based on the local outlier factor (LOF), which represents the likelihood of an entity being an outlier. Experimental results indicate that our method is more sensitive than JPlag, which uses greedy string tiling for detecting plagiarism-suspected code pairs. Further, the adaptive threshold based on the LOF is shown to be effective, and the detection performance shows high sensitivity with negligible loss of specificity, compared with that using a fixed threshold.

• Journal of Families and Better Life
• /
• v.19 no.2
• /
• pp.23-30
• /
• 2001

The purpose of this study was to examine the effect of the traditional fairy tales based program on the improvement of preschoolers level of distributive justice reasoning. The program was developed on the six Korean fairy tales which deal with the sharing problem among the friends and the families. The subjects were seventy-six, 4- and 5-year-old children selected from two kindergartens in Seoul and Ichon. Solomon 4-group experimental design was used. Each children were assigned for 2 experimental groups and for 2 control groups. Before the intervention, the subjects in experimental group 1 and control group 1 were interviewed individually with story dilemmas for their distributive justice reasoning. For eight-week period, the program based on six Korean traditional fairy tales were used as an intervention. After the intervention, all the subjects were interviewed individually with another story dilemmas. The data were analyzed in SPSS Win 10.0 program, by frequency, percentile, mean, standard deviation, paired t-test and independent t-test. As a result, the children in experimental groups had higher level of distributive justice reasoning than those in control groups. That is, program based on the traditional fairy tales gave positive effect on preschoolers distributive justice reasoning.

• Journal of Korea Game Society
• /
• v.1 no.1
• /
• pp.102-111
• /
• 2001

The purpose of this study is to empirically test developed on the basis of the literature review regarding customer satisfaction management and gamer's satisfaction factor To analyze the date collected from 1999 respondents. Frequency Corsstabs Oneway ANOVA analysis was performed with SPSS/PC+ Window 7.5. The results can be sumarized as follows. First, Dissatisfaction factor of game service is game possible area, game being cut off and game use charge. Second, Solution suvject is 'no service' in underground area/big size crowed area and game being cut of. Finally, The most impotant aspects when a customer visits Korea Movement Technology are the friendly attitude of the employee, problem-solving and papid pesponse to inquirce.