• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.31 no.3D
• /
• pp.343-353
• /
• 2011

The unsignalized intersections in a community road in the city of Seoul have 3,753 traffic accidents(9%) of total 41,702 cases in 2008, not high in the occurrence rate of traffic accidents, but seem to have a quite high potential of accidents due to the unreasonable and insufficient operation of systems and facilities in the part of traffic foundations. In particular, the un-signalized intersections in a community road have an insufficient measure for safety as compared to the crossroads with signals, and there are few analysis of traffic accidents and domestic researches on the model of affecting factors. Our country also has no concept of passing priority in operating a crossroad without signals, differently from foreign countries, so the researches and safety measures for improving the safety of a crossroad without signals in a community road are urgent. Therefore, This study set out to analyze the road conditions, traffic conditions, and traffic environment conditions on unsignalized intersection, to identify the elements that would impose obstructions in safety, and develop a traffic accident prediction model to evaluate the safety of an unsignalized intersection using the correlation between the elements and an accident. In addition, the focus was made on suggesting appropriate traffic safety policies by dealing with the danger elements in advance and on enhancing the safety on intersection in developing a traffic accident prediction model for an unsignalized intersection.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.14 no.3
• /
• pp.9-23
• /
• 2015

A lane change maneuver which has a high driver cognitive workload and skills sometimes leads to severe traffic accidents. In this study, the Advanced Lane Change Assist System (ALCAS) was developed to assist with the automatic lane changes in merging sections which is mainly based on an automatic control algorithm for detecting an available gap, determining the Optimal Lane Change Start Point (OLCSP) in various traffic conditions, and positioning the merging vehicle at the OLCSP safely by longitudinal automatic controlling. The analysis of lane change behavior and modeling of fundamental lane change feature were performed for determining the default parameters and the boundary conditions of the algorithm. The algorithm was composed of six steps with closed-loop. In order to confirm the algorithm performance, numerical scenario tests were performed in various surrounding vehicles conditions. Moreover, feasibility of the developed system was verified in microscopic traffic simulation(VISSIM 5.3 version). The results showed that merging vehicles using the system had a tendency to find the OLCSP readily and precisely, so improved merging performance was observed when the system was applied. The system is also effective even during increases in vehicle volume of the mainline.

• Journal of Science and Technology Studies
• /
• v.2 no.2 s.4
• /
• pp.145-189
• /
• 2002

This paper explores into the potential contribution of welfare science and technology(WST) to meeting the challenges of ageing. Drawing on the literature about gerontechnology, this paper considers the application of scientific knowledge for welfare of an aging population. WST for the improvement of the daily functioning of the elderly people can not only prevent, delay or compensate for the declines or impairments of coginitive and physical functions (by assistive technology) but also enhance personal ability to overcome problems either by supporting the person's abilities (by supportive technology) or by changing the environment (by public welfare technology). This paper draws attention to a paradigm change in the conceptualization of disability and its ramifications for the role of technology and aging. A range of approaches such as Barrier-Free design, Universal Design points to new directions of WST in which products and services are devised to improve the quality of life for all people, and hence enhancing the socio-economic vitality. It is suggested that the future of welfare science and technology will be based in large measure on its goal to reduce or prevent individual and structural lag in the relationships between people and their environments. Addressing issues of the broader physical and social environment will emphasize the goal of prevention and the view that environmental needs for aging population are changing over time.

• Korean Journal of Social Welfare
• /
• v.59 no.4
• /
• pp.5-34
• /
• 2007

This study explores the effects of philanthropy education for elementary school students by using a mixed method. To examine the effects of philanthropy education, two different approaches in research methods are conducted with different data collected from different target groups on the same phenomenon: a) experimental designs to analyze students' change(prosocial behaviors) by philanthropy education program performed in a summer camp(43 participants) and elementary schools(162 students); and b) qualitative analysis on students' changes in perceptual, attitudinal, and behavioral aspects by students' diary and memorandum(66 participants) and intensive interviews with teachers(5 teachers) and parents(4 mothers). The analysis of both quantitative and qualitative results shows that philanthropy education has effects on students' changes in diverse aspects including prosocial behavior. First, the results of quantitative analysis show that in every component of the prosocial behavior such as helping, being kind, empathizing, sharing, protecting, and cooperating, students have positive changes after philanthropy education. Such changes are statistically significant as well. Second, the results of qualitative analysis show that students after having philanthropy education display positive changes in diverse aspects. Particularly, the quantitative results are converged with the qualitative results from students, parents, and teachers. On the other hand, unique finding from qualitative analysis is that students after having philanthropy education can have fundamental changes in their personality. Such a change is commonly confirmed by students, parents, and teachers. This study makes it possible to compare results or to validate, confirm, or corroborate quantitative results with qualitative findings on the effects of philanthropy education for students.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.46 no.4
• /
• pp.382-391
• /
• 2019

This study was aimed to assess the new trial for minimal cavity preparation in composite restoration combined with resin infiltration, focusing at application sequence. 32 human primary molars with early carious lesions around small cavity were selected and randomly divided into two groups, according to the sequence of cavity preparation (P), composite filling (F) and resin infiltration (I) as IPF and PFI group. Each group was assessed about amount of tooth reduction, features of resin infiltration, and marginal leakage around restoration. Amount of tooth reduction evaluated using micro-CT was decreased compared with the original lesion size in both groups. Features of resin infiltration were verified under confocal laser scanning microscopy. In both groups, infiltrant resin was found on all around the composite and maintained in spite of extent of decalcification even after artificial caries induction. Marginal micro leakage assessed with silver nitrate immersion and micro-CT was found more frequently in PFI group. The technique combining resin infiltration and composite restoration might ensure better adhesion prognosis as applied by the sequence of resin infiltration, cavity preparation, and composite filling. This new trial was thought meaningful in minimizing the cavity size and contributing to minimal invasive dentistry.

• Child Health Nursing Research
• /
• v.21 no.1
• /
• pp.20-27
• /
• 2015

Purpose: The purpose of this study was to investigate factors affecting childhood asthma and atopic dermatitis. Methods: For this study, data for 1,170 children (1-11 years) from the Fifth Korean National Health and Nutrition Examination Survey (KNHANES V-2, 2011) were analyzed. First correlation matrices were computed to test the normality of every data set and then to be in accordance with the real demographic composition, data were added weight before being analyzed. Results: The child with asthma of a three generation family (OR=3.91, 95% CI [1.33, 11.45], p=.013) compared with a two generation family showed higher asthma development, and maternal asthma (OR=9.71, 95% CI [2.66, 35.40], p=.001) showed higher asthma development in child. The only factor affecting atopic dermatitis was parental perceptions of child health: poor (OR=3.40, 95% CI [1.29, 8.98], p=.014). Conclusion: These results suggest that childhood asthma and atopic dermatitis are both affected by parental perceptions of child health. Accordingly, management and support programs for children who have asthma and/or atopic dermatitis and their families should be comprehensive and also give attention to any other health problems because health perception represents quality of life.

• Journal of the HCI Society of Korea
• /
• v.5 no.1
• /
• pp.37-43
• /
• 2010

Twitter has been continuously growing since October, 2006. Especially, not only the users and the number of messages have been increasing but also a new concept in social networking called 'micro blogging' has diffused. Within Korea, service such as 'me2day' has already been introduced and the improvement of internet accessibility within mobile devices is expected to expand the 'micro blogs'. In this point, this research is executed to study the new medium, 'micro blog'. To do so, we collected and analyzed Twitter logs of Korean users. Especially, we were curious about the extreme heavy users using Twitter, despite of the linguistic and cultural barrier of the foreign service. Who they are, why and how they use the 'micro blog'. First, we reviewed the general aspect of followers and messages by collecting a certain number of random samples. Using the Lorenz curve we found out that there was the imbalance within the users and based on this phenomenon we deducted an extreme heavy user group. In order to perform further analysis, log analysis was performed on the extreme heavy users. As the result, the users used multiple mobile and desktop 'Twitter' clients. The usage pattern was similar to that of internet usage time but was used during their "micro" time. The users using 'Twitter' not only to spread messages about important information, special events and emotions, but also as a habitual 'chatting tool' to express ordinary personal chats similar to SMS and IM services. In this research, it is proved that 68% of the total messages were ordinary personal chats. Also, with 24% of the total messages were retweets, we were able to find out that virtually connected 'people' and 'relationships' acted as the dominant trigger of their articulation.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.3A
• /
• pp.232-239
• /
• 2011

IEEE 802.11n standard provides a framework for new link adaptation. A station can request that another station provide a Modulation and Coding Scheme (MCS) feedback, to fully exploit channel variations on a link. However, if the time elapsed between MCS feedback request and the data frame transmission using the MCS feedback becomes bigger, the previously received feedback information may be obsolete. In that case, the effectiveness of the feedback-based link adaptation is compromised. If a station can estimate how fast the channel quality to the target station changes, it can improve accuracy of the link adaptation. The contribution of this paper is twofold. First, through a thorough NS-2 simulation, we show how the coherence time affects the performance of the MCS feedback based link adaptation of 802.11n networks. Second, this paper proposes an effective algorithm for coherence time estimation. Using Allan variance information statistic, a station estimates the coherence time of the receiving link. A proposed link adaptation scheme considering the coherence time can provide better performance.

• Journal of KIISE:Databases
• /
• v.30 no.5
• /
• pp.451-463
• /
• 2003

Recently, there have been various research efforts to develop strategies for accelerating OLAP operations on huge amounts of spatio-temporal data. Most of the work is based on multi-tree structures which consist of a single R-tree variant for spatial dimension and numerous B-trees for temporal dimension. The multi~tree based frameworks, however, are hardly applicable to spatio-temporal OLAP in practice, due mainly to high management cost and low query efficiency. To overcome the limitations of such multi-tree based frameworks, we propose a new approach called Hilbert Cube(H-Cube), which employs fractals in order to impose a total-order on cells. In addition, the H-Cube takes advantage of the traditional Prefix-sum approach to improve Query efficiency significantly. The H-Cube partitions an embedding space into a set of cells which are clustered on disk by Hilbert ordering, and then composes a cube by arranging the grid cells in a chronological order. The H-Cube refines cells adaptively to handle regional data skew, which may change its locations over time. The H-Cube is an adaptive, total-ordered and prefix-summed cube for spatio-temporal data warehouses. Our approach focuses on indexing dynamic point objects in static spatial dimensions. Through the extensive performance studies, we observed that The H-Cube consumed at most 20% of the space required by multi-tree based frameworks, and achieved higher query performance compared with multi-tree structures.

• Archives of design research
• /
• v.19 no.2 s.64
• /
• pp.151-162
• /
• 2006

The purpose of this thesis is to upgrade brand logo's equity by objective and professional evaluating tool. A brand logo is the main factor in making brand equity, but many times a brand logo is decided without objective judgment because making a logo is considered an intuitive process. To minimize the poor judgment by non-experts, a brand logo needs objective numerical grading tool. Thus, a brand logo is a factor in making a brand identity, not only brand image. That is why brand logo must be chosen by an expert's object judgment. The concrete method to obtain a objective, and at the same time professional grading tool which can De used for the developing and verifying process for a brand logo is as below-first, considering brand judgment from various angles through existing literature, I found various logo grading factors and then extracted them with professional identity designer's subjective consideration. second, applying extracted factors to actual logo grading, verify as a efficient design management tool