• The Journal of The Korea Institute of Intelligent Transport Systems
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• 제19권5호
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• pp.40-51
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• 2020

Much time has passed since Korea's expressway congestion-threshold speed was revised in 2011. In the meantime, various expressway environments have changed owing to improved performance of vehicles, expanded operations of transport competition (i.e., the KTX), and increased speed limits along some expressway sections. In addition, the speed that expressway users expect to travel at is also increasing. Therefore, through a survey, this study investigates expressway users' perceptions of congestion, and reviews the adjustment of the expressway speed congestion threshold by analyzing expressway traffic flow. One result of the survey confirms that the threshold speed expressway users consider to be congestion has slightly increased. Analyzing traffic and speed data through a K-means algorithm found that the threshold speed for congestion is 60 km/h. In addition, assuming the congestion threshold speed increase from 40 km/h to 50 km/h and 60 km/h, frequently congested expressway sections are identified, determining that 50 km/h is appropriate as a congestion threshold for proper expressway mobility management.

• Journal of Korean Academy of Fundamentals of Nursing
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• 제2권1호
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• pp.87-101
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• 1995

This study was conducted with the subject of showing the importance of early rehabilitation and exercise therapy in patients who have stroke, of confirming the adavntage of ward exercise conducted by nurse, which had been conducted mainly by physical therapist only in physical thrapy room and of developing the exercise program as the independent rehabilitation nursing intervention. A total of 62 patients were selected as object from April, 5th, to May, 17th, 1995, who had been hospitalized in K medical center, and the half of them were assigned to Experimental group in ramdom assignment using a coin. It was ADL check list tool developed by Kang and Ward Exercise Program developed by the researcher that were used as a treatment. Ward Exercise Program was conducted by the reseacher and the physical therapist measured ADL score before and after Ward Exercise Program. The data were analyzed using ANOVA, pearson correlation, Chi-Square test and the effect of Ward Exercise Program was analyzed by t-tast. The result of this study is as follows. 1. The experimental group showed eminent improvement of ADL compared with the counter group with statistical significance. In eating(t=6.10, df=60, p=.000), personal hygiene performing(t=4.86, df=60, p=.000), wearing(t=5.86, df=60, p=.000), elimination(t=7.89, df=60, p=.000), mobility on the bed(t=13.36, df=60, p=.000), moving(t=9.11, df=60, p=.000), walking(t=7.45, df=60, p=.000) 2. There was no qualitative difference between experimental group and control group with the significance of $p{\le}.05$. 3. There was no relation between the general condition and the difference of ADL, while there was significant relation between the starting point of exercise and the difference of pre-exercise and post exercise ADL. As a result, it should be emphasized that the early rehabilitation and exercise therapy are important in patients who have stroke, and that it is necessary to extend the exercise therapy to the ward. Therefore, this Ward Exercise Program could be recommended as a independent clinical exercise nursing intervention in rehabilitation nursing of patients who have stroke.

• Journal of Periodontal and Implant Science
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• 제38권1호
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• pp.97-102
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• 2008

Purpose: Periodontal intrabony defects have great deal of importance since they contribute to the development of periodontal disease. Current treatment regimens for intrabony defects involve grafting of numerous bony materials, GTR using biocompatible barriers, and biomodification of root surface that will encourage the attachment of connective tissue. Xenograft using deproteinized bovine bone particles seems to be very convenient to adjust because it doesn't require any donor sites or imply the danger of cross infections. These particles are similar to human cancellous bone in structure and turned out to be effective in bone regeneration in vivo. We here represent the effectiveness of grafting deproteinized bovine bone particles in intrabony defect and furcation involvements that have various numbers of bony walls. Materials and methods: Open flap debridement was done to remove all root accretions and granulation tissue from the defects within persisting intrabony lesions demonstrating attachment loss of over 6mm even 3 months after nonsurgical periodontal therapy have been completed. Deproteinized bovine bone particles($BBP^{(R)}$, Oscotec, Seoul) was grafted in intrabony defects to encourage bone regeneration. Patients were instructed of mouthrinses with chlorohexidine-digluconate twice a day and to take antibiotics 2-3 times a day for 2 weeks. They were check-up regularly for oral hygiene performance and further development of disease. Probing depth, level of attachment and mobility were measured at baseline and 6 months after the surgery. The radiographic evidence of bone regenerations were also monitored at least for 6 months. Conclusion: In most cases, radio-opacities increased after 6 months. 2- and 3-wall defects showed greater improvements in pocket depth reduction when compared to 1-wall defects. Class I & II furcation involvements in mandibular molars demonstrated the similar results with acceptable pocket depth both horizontally and vertically comparable to other intrabony defects. Exact amount of bone gain could not be measured as the re-entry procedure has not been available. With in the limited data based on our clinical parameter to measure pocket depth reduction following $BBP^{(R)}$ grafts, it was comparable to the results observed following other regeneration techniques such as GTR.

• Journal of dental hygiene science
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• 제14권3호
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• pp.417-423
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• 2014

The aim of this study was to evaluate the relationship between prosthetic status and health related quality of elderly by using EuroQol-5 dimension (EQ-5D) which is a standardized instrument used as a measure of health outcome. Data from 1,179 elderly subjects (over 65 years old) from the fifth Korea National Health and Nutrition Examination Survey were used in our analysis. Oral examination were conducted to obtain wearing prosthetic and needed prosthetic. EQ-5D is a widely used health condition measuring instrument. It consists of the five dimensions: Mobility, Self-care, Usual activities, Pain/discomfort and Anxiety/depression. EQ-5D index is a score calculated out of a weighting system. In this study, the mean score of the EQ-5D index among the elderly was 0.86. For EQ-5D index gender, female showed statistically significantly lower quality of life than male. The related factors EQ-5D index, when the lower demand for fixed prosthodontics and full denture. Wearers in partial and complete denture than non-wearers showed higher EQ-5D index. In order to improve EQ-5D index among the elderly who demand prosthetic status, which has lost its function through providing proper dental prostheses.

• Korean Journal of Crystallography
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• 제7권1호
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• pp.44-56
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• 1996

CuInTe2 synthesised in a horizontal electric furnace was found to be polycrystalline. Single crystals of CuInTe2 were grown with the vertical Bridgman technique. The structure, Hall effect of the crystals were measured in the temperature range 30 to 293K. Both the polycrystals and single crystals of CuInTe2 were tetragonal in structure. The lattice constants of the polycrytals were measured as a=6.168Å and c=12.499Å, with c/a=2.026, these of the single crystals were measured as a=6.186Å and c=12.453Å, with c/a=2.013. The growth plane of the oriented single crystals was confirmed to be a (112) plane from the back-reflection Laue patterns. The Hall effect of the CuInTe2 single crystals was measured with the method of van der Pauw The Hall data of the samples measured at room temperature showed a carrier concentration of 2.14×1023holes/m3, a conductivity of 739.58Ω-1m-1, and a mobility of 2.16×10 -2m 2/V·s for the sample perpendicular to the c-axis. Values of 1.51×1023holes/m3, 717.55Ω-1m-1, and 2.97×10-2 m2/V·s were obtained for the sample parallel to the c-axis. The Hall coefficients for the samples both perpendicular and parallel to the c-axis in the temperature range 30K to 293K were always positive values. Thus the CuInTe2 single crystal was determined to be a p-type semiconductor.

• Journal of the Economic Geographical Society of Korea
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• 제12권4호
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• pp.319-343
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• 2009

This paper considers some kinds of socio-spatial constraints and strategies for overcoming them which immigrant workers in Korea have experienced in their work-place and life-space, with an analysis of questionnaire data and of direct interview materials on them. Though they appear somewhat satisfactory or positive with their work-place, this can be seen as a hypocritical or false attitude rather than a real one: they are forced to work with long hours (more than 70 hours per week) and rigid controls in the other' territory. Their daily life-spaces also are severe: they can be hardly embedded in an existing community with a sense of place due to serious institutional and interaction constraints, even though they seem to have a basic mobility to survive in life-spaces. In order to escape or alleviate such local constraints, they try to constitute multi-scalar (local, trans-regional, and transnational) networks, and to find informations and means to resolve or cope with them. However, this kind of endeavors of immigrant workers to make a trans-national network and social space has a limitation for them to be free entirely from constraints, which might be strengthened with a lack of geographical knowledge of them. Then immigrant workers in Korea live ineluctably with not only hybrid national identity but also with disturbed local identity in an aliened workplace and life-spaces.

• The KIPS Transactions:PartC
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• 제14C권5호
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• pp.417-424
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• 2007

Mesh networks using WLAN technology have been paid attention as a key wireless access technology. However, many technical issues still exist for its successful deployment. One of those issues is the routing problem that addresses the path setup through a WLAN mesh network for the data exchanges between a station and a wired network. Since the characteristics of a WLAN mesh network can be very dynamic, the use of single routing protocol would not fit for all environments whether it is reactive or proactive. Therefore, it is required to develop an adaptive routing protocol that modifies itself according to the changes in the network parameters. As a logical first step for the development, an analytical model considering all the dynamic features of a WLAN mesh network is required to evaluate the performance of a reactive and a proactive routing scheme. In this paper, we propose an analytical model that makes us scrutinize the impact of the network and station parameters on the performance of each routing protocol. Our model includes the size of a mesh network, the density of stations, mobility of stations. and the duration of network topology change. We applied our model to the AODV that is a representative reactive routing protocol and DSDV that is a representative proactive routing protocol to analyze the tradeoff between AODV and DSDV in dynamic network environments. Our model is expected to help developing an adaptive routing protocol for a WLAN mesh network.

• KIPS Transactions on Computer and Communication Systems
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• 제9권3호
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• pp.67-76
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• 2020

With the fast development in wireless communications and vehicular technologies, vehicular ad hoc networks (VANETs) have enabled to deliver data between vehicles. Recently, VANETs introduce a Vehicular Cloud (VC) model for collaborating to share and use resources of vehicles to create value-added services. To construct a VC, a vehicle should search vehicles that intend to provide their own resource. The single-hop search cannot search enough provider vehicles due to a small coverage and non-line-of-sights of communications. On the other hand, the multi-hop search causes very high traffics for large coverage searching and frequent connection breakages. Recently, many Roadside Units (RSUs) have been deployed on roads to collect the information of vehicles in their own coverages and to connect them to Internet. Thus, we propose a RSU-aided vehicular resource search and cloud construction mechanism in VANETS. In the proposed mechanism, a RSU collects the information of location and mobility of vehicles and selects provider vehicles enabled to provide resources needed for constructing a VC of a requester vehicle based on the collected information. In the proposed mechanism, the criteria for determining provider vehicles to provide resources are the connection duration between each candidate vehicle and the requester vehicle, the resource size of each candidate vehicle, and its connection starting time to the requester vehicle. Simulation results verify that the proposed mechanism achieves better performance than the existing mechanism.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제18권2호
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• pp.287-293
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• 2017

The purpose of the study was to analyze the effects of work experience during higher education on employment. In particular, the study analyzed the difference in employment and permanent employment according to work experience or internship. In addition, the effects of the relatedness of college major and work experience as well as internship on college graduates' employment or permanent employment were investigated. The data came from the 2013 Graduates Occupational Mobility Survey (GOMS). The study covered the chi-square test and logistic regression analysis. The study found that there was a significant difference in the employment and permanent employment among the groups classified by work experience or internship. Internship had a positive effect on college graduates' permanent employment. Based on the study results, this study suggests that policies for internship during higher education need to be enhanced. The match between employment and the field of study in college needs to be increased. Interventions and policies for the establishment of competency-based employment should be improved.

• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.131-131
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• 2013

A single-layer graphene has been uniformly grown on a Cu surface at elevated temperatures by thermally processing a poly(methyl methacrylate) (PMMA) film in a rapid thermal annealing (RTA) system under vacuum. The detailed chemistry of the transition from solid-state carbon to graphene on the catalytic Cu surface was investigated by performing in-situ residual gas analysis while PMMA/Cu-foil samples being heated, in conjunction with interrupted growth studies to reconstruct ex-situ the heating process. The data clearly show that the formation of graphene occurs with hydrocarbon molecules vaporized from PMMA, such as methane and/or methyl radicals, as precursors rather than by the direct graphitization of solid-state carbon. We also found that the temperature for vaporizing hydrocarbon molecules from PMMA and the length of time the gaseous hydrocarbon atmosphere is maintained, which are dependent on both the heating temperature profile and the amount of a solid carbon feedstock are the dominant factors to determine the crystalline quality of the resulting graphene film. Under optimal growth conditions, the PMMA-derived graphene was found to have a carrier (hole) mobility as high as ~2,700 cm2V-1s-1 at room temperature, superior to common graphene converted from solid carbon.