• Journal of Internet Computing and Services
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• v.13 no.2
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• pp.41-49
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• 2012

Wireless network support and extended mobile network environment with exponential growth of smart phone users allow us to utilize the network anytime or anywhere. Malicious attacks such as distributed DOS, internet worm, e-mail virus and so on through high-speed networks increase and the number of patterns is dramatically increasing accordingly by increasing network traffic due to this internet technology development. To detect the patterns in intrusion detection systems, an existing research proposed an efficient algorithm called the jumping window algorithm and analyzed approximately 2,000 patterns in Snort 2.1.0, the most famous intrusion detection system. using the algorithm. However, it is inappropriate from the number of TCAM lookups and TCAM memory efficiency to use the result proposed in the research in current environment (Snort 2.9.0) that has longer patterns and a lot of patterns because the jumping window algorithm is affected by the number of patterns and pattern length. In this paper, we simulate the number of TCAM lookups and the required TCAM size in the jumping window with approximately 8,100 patterns from Snort-2.9.0 rules, and then analyse the simulation result. While Snort 2.1.0 requires 16-byte window and 9Mb TCAM size to show the most effective performance as proposed in the previous research, in this paper we suggest 16-byte window and 4 18Mb-TCAMs which are cascaded in Snort 2.9.0 environment.

• Spatial Information Research
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• v.22 no.4
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• pp.89-102
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• 2014

The establishment and operation of Region-based Teleworking Centers(RTC) in Korea is in the initial stage at the moment. Although some studies have been conducted on telecommuting at home, few studies have been performed on the effects of all-out expansion and diffusion of region-based Teleworking Centers. Therefore, this study analyzed the reduction effect of commuting distance which is possible to obtain from the establishment of Teleworking Centers, based on the network in the Seoul Metropolitan Area, Subsequently, quantitative reduction of the effects of $CO_2$ were calculated from region-based Teleworking Centers. The results of the analysis indicated that region-based Teleworking Centers could reduce a total of 911 tons of $CO_2$ per day. When applying these results to 258 working days per year (according to Statistics Korea), 235,056 tons of $CO_2$ can be reduced annually by the establishment of Teleworking Centers. With quantity on environmental utility to be obtained from the establishment of Teleworking Centers, this study can be utilized as a guideline for selecting effective locations of Teleworking Centers in the future. It can also be helpful in decisions to determine the priority of extending operations of Teleworking Centers through comparisons among administrative districts.

• Korean Journal of Agricultural Science
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• v.43 no.4
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• pp.650-655
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• 2016

Gears are components of transmission which transmit the power of an engine to a machine and offer numerous speed ratios, a compact structure, and high efficiency of power transmission. Gear train design in the automotive industry uses simulation software. However, PTO (Power Take-Off) gear design for agricultural applications uses the empirical method because of the wide range of load fluctuations in agricultural fields. The PTO is an important part of agricultural tractors which transmits the power to various tractor implements. Therefore, a simulation was essential to the optimal design of the PTO. When the PTO gear is optimally designed, there are many advantages such as low cost, reduced size, and light weight. In this study, we conducted the bending and contact safety factor simulation for the PTO gear of an agricultural tractor. The bending and contact safety factors were calculated on ISO 6336 : 2006 by decreasing the face widths of the PTO pinion and wheel gear from 18 mm at an interval of 1 mm. The safety factor of the PTO gear decreased as the face width decreased. The contact safety factors of the pinion and wheel gear were 1.45 and 1.53, respectively, when the face width was 18 mm. The simulation results showed that the face width of the PTO gear should be greater than 9 mm to maintain the bending and contact safety factors higher than 1. It would be possible to reduce the weight of the PTO gear for different uses and working conditions. This study suggests that the possibility of designing an optimal PTO gear decreases as its face width decreases.

• Journal of Digital Convergence
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• v.10 no.9
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• pp.47-57
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• 2012

This study was conducted to investigate the pre-service teacher's perception of the possibility of using smartphones in the classroom, moreover, to confirm the policy related to using smartphones in schools. For the objectives, this study, firstly, investigated the pre-service teacher's awareness of having cellphones in the classroom, secondly, analyzed the pre-service teacher's opinion of using smartphones for educational objectives and elements for those investigated objectives, finally, investigated the school policy for educational objectives of using smartphones. The participants of this study were 146 pre-service teachers among three universities in Seoul. The results showed that the pre-service teachers opposed using cellphones in the classroom. Next, it was found that most of them had smartphones and they knew how to use them effectively. For the aspects of educational use of smartphones, they recognized that smartphones could be used as a smart educational tool, an efficient teaching and learning tool, and an assistant tool for teaching and learning. In order to use smartphones for the investigated educational tools, the learning contents, the ways of teaching and learning, and the technical support of the school should be prepared. Finally, the pre-service teachers thought that the school policy should be changed in order to use smartphones for educational objectives, and the school policy with regard to using smartphones in the classroom should be decided by the teachers. Most of all, for the educational use of smartphones, the pre-service teachers believed that the change of the students' perception was the most significant.

• Journal of Digital Convergence
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• v.15 no.11
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• pp.471-484
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• 2017

The present study explored factors that influence consumers' benefit expectancy about telemedicine service. Responses from a national online survey of 927 adults (aged 19-59), collected in January 2016, were analyzed with multiple regression analysis. The results revealed: (1) Health consciousness positively influenced all three benefit expectancies (all ps < .05); (2) Doctor-patient communication efficacy positively influenced expectancy for convenience improvement (${\beta}=.107$, p < .01) and service quality improvement (${\beta}=.086$, p < .05); (3) Use of health-related smart applications contributed to positive expectancy for service quality improvement (${\beta}=.081$, p < .05) and cost-saving (${\beta}=.067$, p < .05). Some of the relationships were moderated by gender and residence. This convergence study, which examined public's perception about telemedicine from the perspectives of consumer psychology, media, and public health, provides practical implications to promote telemedicine service and educate consumers about it.

• Journal of the Korean Society for Library and Information Science
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• v.51 no.3
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• pp.189-213
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• 2017

Conducted within the framework of the Information Use Environments, this study analyzed the characteristics of students in high schools, identified the typical problems of the students and their information sources to resolve the problems, and analyzed the settings the students use daily. The survey questionnaires were distributed to 220 students in 3 different high schools located in the affluent community area of K-Ku in Seoul particularly known for high academic interests. 188 questionnaires were collected and analyzed using SPSS 24. The findings indicate that the students's attitudes toward education, going to college, and changes and innovations were positive. that they chose the internet as their most favorite information sources for problems, and that 21 problems in 7 self-categories were identified as the students' typical problems, and that the problems within emotional and cognitive self were considered the most important. It was interesting that the students use parents and siblings as information sources to resolve the problems within emotional and cognitive self, although they chose the internet as their favorite information sources in general. The settings that students use daily during weekdays were homes, schools, smart devices. academic tutoring centers, PC or laptop in order. The students' daily settings for weekends were homes, academic tutoring centers, restaurants, PC or laptop in order. These setting was statistically different according to gender and grades. The implications of this study were to suggest the further research questions and to show the application of the IUEs for understanding high school students in a specific setting. Further studies are needed to understand high school students in different contexts.

• Spatial Information Research
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• v.23 no.1
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• pp.59-68
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• 2015

As part of an effort to leap smart cadastre system by doing rearrangement of various mismatches in the land register, the cadastre renovation project is being recently conducted. In response to this demand, this paper proposes an image-based rapid parcel boundary demarcation plan using the high resolution aerial image with a GSD (Ground Sample Distance) of 5cm that matches to real ground boundary situation in residential area. To review the feasibility and accuracy of this proposed methodology, we compared the accuracy of parcel boundary point and parcel area extracted from the digital stereo plotting on the basis of results of cadastral boundary surveying and land register over the selected two test areas. The comparative accuracy result of all boundary points by digital stereo plotting is satisfied with accuracy requirement according to the criteria of the enforcement regulation of cadastral surveying, whereas it exceeded allowable error of ${\pm}0.07m$, more strictly specified in the Special Act on Cadastral Renovation. And about 20% of the total 70 parcels extracted by digital plotting are out of area tolerance in Jecheon study area, and 10% of the total 19 parcels in Suwon study area. The parcels exceeding accuracy limit are mostly due to the occlusion caused by building roof or eaves, and the obstacles such as trees existing on the boundary. Furthermore, an object identification is impossible in image because of vague boundary reference in case of nonexistence of man-made structures or natural features. Therefore, the utilization of boundary identification stickers is recommended as a solution for these types of land parcel.

• Journal of the Korea Convergence Society
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• v.7 no.6
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• pp.13-21
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• 2016

In this paper we are trying to explain the effect of temperature on polymer membrane exchange water electrolysis (PEMWE) and polymer membrane exchange fuel cell (PEMFC) simultaneously. A comprehensive studying approach is proposed and applied to a 50Watt PEM fuel cell system in the laboratory. The monitoring process is carried out through wireless LoRa node and gateway network concept. In this experiment, temperature sensor measure the temperature level of electrolyzer, fuel cell stack and $H_2$ storage tank and transmitted the measured value of data to the management control unit (MCU) through the individual node and gateway of each PEMWE and PEMFC. In MCU we can monitor the temperature and its effect on the performance of the fuel cell system and control it to keep the lower heating value to increase the efficiency of the fuel cell system. And we also proposed a mathematical model and operation algorithm for PEMWE and PEMFC. In this model, PEMWE gives higher efficiency at lower heating level where as PEMFC gives higher efficiency at higher heating value. In order to increase the performance of the fuel cell system, we are going to monitor, communicate and control the temperature and pressure of PEMWE and PEMFC by installing these systems in a building of university which is located in the southern part of Korea.

• The KIPS Transactions:PartC
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• v.17C no.4
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• pp.307-314
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• 2010

Recently, it is proved that contactless smart-card based RFID tags, which is used for proximity authentication, are vulnerable to relay attacks with various location-based attacks such as distance fraud, mafia fraud and terrorist fraud attacks. Moreover, distance bounding protocols have been researched to prevent these relay attacks that can measure the message transmitted round-trip time between the reader and the tag. In 2005, Hancke and Kuhn first proposed an RFID distance bounding protocol based on secure hash function. However, the Hancke-Kuhn protocol cannot completely prevent the relay attacks because an adversary has (3/4)$^n$ attack success probability. Thus, this paper proposes a new distance-bounding protocol for light-weight RFID systems that can reduce to (5/8)$^n$ for the adversary's attack success probability. As a result, the proposed protocol not only can provide high-space efficient based on a secure hash function and XOR operation, but also can provide strong security against the relay attacks because the adversary's attack success probability is optimized to (5/8)$^n$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.6
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• pp.771-777
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• 2017

This study investigated the rheological properties of Calrose rice flour dispersions as well as the effects of different thawing methods (steamer, smart oven, and microwave oven) on quality characteristics of frozen turmeric rice. Apparent viscosity, consistency index, and yield stress significantly increased at higher rice flour concentrations. Magnitudes of storage modulus and loss modulus significantly increased with elevation of rice flour concentration. Frozen turmeric rice thawed using a steamer had the highest moisture content and largest size (length, width, and thickness) among all thawing methods. The L values of turmeric rice after thawing using a steamer was significantly higher than those of other thawing methods. The a value of turmeric rice after thawing using a steamer was significantly lower than those of other thawing methods. Textural properties (hardness, adhesiveness, springiness, cohesiveness, brittleness, and chewiness) of frozen turmeric rice after thawing using a steamer were significantly lower than those of other thawing methods. Therefore, it can be concluded that frozen turmeric rice after thawing using a steamer might be desirable for improvement of texture.