• Journal of rehabilitation welfare engineering & assistive technology
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• v.9 no.3
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• pp.195-201
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• 2015

In this study, IT education contents have been developed based on the u-Learning approach for people with hearing impairment, focusing on allowing the user to learn from anywhere and anytime. Specifically, this study applies HTML5 to implementing IT education contents(JSP, Oracle) for the deaf because HTML5 enables the learner to access the contents through both web and mobile device on various platforms including android, Mac OS, and PC etc. The results of this study are as follows: First, the online computer courses are mostly supposed to be compatible with diverse types of mobile devices. However, some of the contents could not be run on applications residing in web and mobile devices because the contents tend to be developed using FLASH. HTML5 is the effective way to overcome the compatibility problem. Second, FLASH and HTML5 contents authoring tools have been compared in terms of their strong and weak points by applying the developed contents to those tools. The study also suggests that the future work would be needed in order to implement wide variety of event functions with HTML5. Lastly, design strategies enabling access through web and mobile devices have been analyzed in accordance with u-Learning design guidelines for the deaf and mobile application accessibility guidelines. However, in the latter case, the future work regarding design guidelines needs to be conducted to improve the educational accessibility depending on the level of impairment.

• Journal of dental hygiene science
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• v.8 no.4
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• pp.323-329
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• 2008

The purpose of this study was to compare the oral health education effect and the satisfaction about the method between SDL and CCI on elementary school students. Method: The subjects of this study were 233 elementary school students in fourth grade (male: 56%, female: 44%) who attended two different elementary schools in Wonju Gangwon-do. They are divided into two groups and instructed by different method of the oral health education, SDL (Self-Directed Learning) and CCI (Conventional Classroom Instruction). The survey was conducted three times, preeducation, just after the education and one week after education. Collected data were analyzed into Chi-square test, Independent t-test and Repeated measure ANOVA using SPSS 12.0 K program. Result: 1. Changes of oral health knowledge: After the education, the average score of the oral health knowledge went up significantly in both groups. 2. Changes of oral health behavior: After the education, the average score of the oral health behavior rose up significantly in both groups and especially just after education, SDL group was recorded higher average score than CCI group. 3. Satisfaction: In both groups, the satisfaction rates about the education method were high (SDL: 88.9%, CCI: 99.1%). The main reason of satisfaction in SDL group was that the students were interested in the method of the education and the main reason of dissatisfaction was that they could not ask a question to the educator.

• Journal of dental hygiene science
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• v.17 no.6
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• pp.472-480
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• 2017

The purpose of this study was to investigate Staphylococcus epidermidis contamination on hands of 20 dental hygienists and 140 equipment surface of 20 dental clinics in a local area, from July to August 2017. The degree of S. epidermidis contamination was measured using a hand plate and a rodac plate and then cultured at $35^{\circ}C$ for 24 hours. Based on hand plate criteria, hand contamination was classified into low, middle, and high groups. Analysis of the variance (ANOVA) of the contamination level of the hand parts of the group surface contamination level of the dental clinic equipment was descriptive statistics after clustering lock count. S. epidermidis contamination was moderate in 55% of the hands of dental hygienists. The area of contamination was 29.45 colony-forming units (CFU) on the palm, followed by the middle finger 7.8 CFU, ring finger 6.4 CFU, and thumb 6 CFU. Medical equipment surface contamination was showed that 3-way handle 4.45 CFU, computer mouse 3.37 CFU, mirror handle 1.60 CFU were higher than other areas. The group with high hand contamination had a high positive correlation with the S. epidermidis contamination of the hand. S. epidermidis contamination level was higher on hands than on the medical equipment surface contamination. Therefore, medical staff should recognize the importance of hand hygiene which should be practiced in the manner suggested by World Health Organization. In addition, the medical team needs to be responsible for performing infection control tasks, implementing infection management guidelines and providing systematic education on infectious disease management.

• Journal of Digital Convergence
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• v.11 no.3
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• pp.273-277
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• 2013

Phishing attacks have been implemented in smarter, more advanced ways with the passage of time. Hackers use intelligent phishing attacks to take over computers and to penetrate internal networks in major organizations. So, in this paper, a model for a prevention of phishing attack spread is conceptual designed in order to protect internal users and sensitive or important information from sophisticated phishing attacks. Internal users simultaneously utilize both external web and organizational mail services. And hackers can take the both side equally as a vector. Thus, packets in each service must be monitored and stored to recognize threatening elements from both sides. The model designed in this paper extends the mail server based security structure used in conventional studies for the protection of Internet mail services accessed by intranet users. This model can build a list of phishing sites as the system checks e-mails compared to that of the method that directly intercepts accesses to phishing sites using a proxy server, so it represents no standby time for request and response processes.

• Journal of Digital Contents Society
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• v.17 no.1
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• pp.51-57
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• 2016

Distributed Computing attempts to harness a massive computing power using a great numbers of idle PCs resource distributed linked to the internet and processes a variety of applications parallel way such as bio, climate, cryptology, and astronomy. In this paper, we develop internet-distributed computing environment, so that we can analyze High Resolution Rainfall Prediction application in meteorological field. For analyze the rainfall forecast in Korea peninsula, we used QPM(Quantitative Precipitation Model) that is a mesoscale forecasting model. It needs to a lot of time to construct model which consisted of 27KM grid spacing, also the efficiency is degraded. On the other hand, based on this model it is easy to understand the distribution of rainfall calculated in accordance with the detailed topography of the area represented by a small terrain model reflecting the effects 3km radius of detail and terrain can improve the computational efficiency. The model is broken down into detailed area greater the required parallelism and increases the number of compute nodes that efficiency is increased linearly.. This model is distributed divided in two sub-grid distributed units of work to be done in the domain of $20{\times}20$ is networked computing resources.

• KIISE Transactions on Computing Practices
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• v.21 no.1
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• pp.13-18
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• 2015

Computational science simulations have been used to enable discovery in a broad spectrum of application areas, these simulations show irregular demanding characteristics of computing resources from time to time. The adoption of virtualized high performance cloud, rather than CPU-centric computing platform (such as supercomputers), is gaining interest of interests mainly due to its ease-of-use, multi-tenancy and flexibility. Basically, provisioning a virtual cluster, which consists of a lot of virtual machines, in a real-time has a critical impact on the successful deployment of the virtualized HPC clouds for computational science simulations. However, the cost of concurrently creating many virtual machines in constructing a virtual cluster can be as much as two orders of magnitude worse than expected. One of the main factors in this bottleneck is the time spent to create the virtual images for the virtual machines. In this paper, we propose a novel technique to minimize the creation time of virtual machine images and improve I/O performance of the provisioned virtual clusters. We also confirm that our proposed technique outperforms the conventional ones using various sets of experiments.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.5
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• pp.219-230
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• 2017

General-Purpose Graphics Processing Units (GPGPUs) build massively parallel architecture and apply multithreading technology to explore parallelism. By using programming models like CUDA, and OpenCL, GPGPUs are becoming the best in exploiting plentiful thread-level parallelism caused by parallel applications. Unfortunately, modern GPGPU cannot efficiently utilize its available hardware resources for numerous general-purpose applications. One of the primary reasons is the inefficiency of existing warp/thread block schedulers in hiding long latency instructions, resulting in lost opportunity to improve the performance. This paper studies the effects of hardware thread scheduling policy on GPGPU performance. We propose a novel warp scheduling policy that can alleviate the drawbacks of the traditional round-robin policy. The proposed warp scheduler first classifies the warps of a thread block into two groups, warps with long latency and warps with short latency and then schedules the warps with long latency before the warps with short latency. Furthermore, to support the proposed warp scheduler, we also propose a supplemental technique that can dynamically reduce the number of streaming multiprocessors to which will be assigned thread blocks when encountering a high contention degree at the memory and interconnection network. Based on our experiments on a 15-streaming multiprocessor GPGPU platform, the proposed warp scheduling policy provides an average IPC improvement of 7.5% over the baseline round-robin warp scheduling policy. This paper also shows that the GPGPU performance can be improved by approximately 8.9% on average when the two proposed techniques are combined.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.5
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• pp.239-246
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• 2017

Communications for mobile sink groups such as rescue teams or platoons bring about a new challenging issue for handling group mobility in wireless sensor networks. Recently, a group region-based approach has been proposed to send data to a mobile sink group. However, it uses excessive flooding for 3 steps (group region discovery, region information notification, and data dissemination) to support mobile sink group. Thus, it causes high energy consumption and data delivery failure. Moreover, its per-sink mobility supporting scheme makes energy consumption and data delivery failure more serious. Thus, this paper proposes an Energy-efficient and Reliable Mobile Group communication protocol (ERMG) to support a mobile sink group, which exploits a virtual grid structure. For the group region discover and notification and the data dissemination, ERMG uses communications with only cell heads of grid cells that manages group sinks. ERMG also uses a per-grid based scheme to support sink mobility. Simulation results show that ERMG has 30% less energy consumption and 6% more desired delivery deadline success ratio than the existing protocols.

• KIPS Transactions on Computer and Communication Systems
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• v.7 no.1
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• pp.9-18
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• 2018

Enhancing performance of big data analytics in distributed environment has been issued because most of the big data related applications such as machine learning techniques and streaming services generally utilize distributed computing frameworks. Thus, optimizing performance of those applications at Spark has been actively researched. Since optimizing performance of the applications at distributed environment is challenging because it not only needs optimizing the applications themselves but also requires tuning of the distributed system configuration parameters. Although prior researches made a huge effort to improve execution performance, most of them only focused on one of three performance optimization aspect: application design, system tuning, hardware utilization. Thus, they couldn't handle an orchestration of those aspects. In this paper, we deeply analyze and model the application processing procedure of the Spark. Through the analyzed results, we propose performance optimization schemes for each step of the procedure: inner stage and outer stage. We also propose appropriate partitioning mechanism by analyzing relationship between partitioning parallelism and performance of the applications. We applied those three performance optimization schemes to WordCount, Pagerank, and Kmeans which are basic big data analytics and found nearly 50% performance improvement when all of those schemes are applied.

• KIPS Transactions on Computer and Communication Systems
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• v.7 no.7
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• pp.165-174
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• 2018

The purpose of this study is to verify the effects of R&D process maturity on product development performance and to verify whether R&D project performance mediating effect. The questionnaire was collected and analyzed to 131 persons related to the R&D work in 55 companies and public institutions performing R&D work. The results of this study are as follows, the effect of R&D process maturity on product development performance and mediating effect of R&D project performance were analyzed by simple and multiple regression analysis. Regression analysis was analyzed by SPSS statistical program. The higher the maturity level of the R&D process, the higher the product development performance and the R&D project performance, and the R&D project performance is partially mediated. It is concluded that it is important to establish and operate a systematic R&D process and to develop a project management methodology suitable for the characteristics of a company in order to improve product development performance. It is expected that if this study are utilized as practical R&D management methodology in corporate management, it will contribute to improvement of company product performance.