• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.1069-1072
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• 2008

As embedded reinforcing suffer from corrosion process, the bond strength and stiffness are reduced, and the structure proceed, eventually, to the deterioration of the concrete, shortening the service life of concrete structures rapidly. In order to deal with these problems, a multitude of researches have been carried out up to this date to evaluate the bond characteristics of RC members, i.e. by artificially inducing rapid corrosion of the reinforcing bar. These artificial corrosion methods, however, could not represent the real condition, resulting in the possibility of overestimation for the RC members in real situation. Accordingly, the purpose of this paper is to investigate the difference in the bond characteristics for RC members corroded by different corrosion methods (artificial rapid method, natural method). For the case of natural corrosion, the brittle failure was observedeven for the case of the area ofcorrosion of 50%. And, the bond strength decreased by about 10% or more for the caseofspecimens with the area of corrosion of 80% or above. Especially, the deterioration of concrete starts at the state of low corrosion level for the case of natural corrosion. Thus, the safety of RC members must be assessed and evaluated more carefully for the naturally corroded members than for the RC concrete members corroded rapidly by artificial method.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.545-553
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• 2009

A lot of long-span marine bridge, which connects land to island or island to island, are being designed and constructed lately in south-west coast in South Korea. In the past, caisson foundations in marine were mainly adopted in construction and stability aspect, however, nowadays with development of pile construction technology, drilled shaft foundations are mainly adopted. As the long span cable stayed bridge and suspension bridge applied with lots of loads are being designed, the scale of pile foundations are getting larger. As the construction cost of substructure including foundation in marine bridges is too high, the appropriate evaluation of the axial bearing capacity of pile becomes a core factor to decide the construction cost of foundation if the drilled shaft is adopted as foundation type of bridge. The evaluation values of skin friction and end bearing capacity of drilled shaft in weathered rock suggested in south Korea are only to introduce the foreign specifications, and most of them are designed in a kind of hard soil layer. Also the allowable load of pile section is less than the expected bearing capacity of pile in the soil condition since the allowable capacity of pile is undervalued. Recently in order to improve this factor the bi-axial hydraulic load test of pile was taken, the data of load transfer analysis of pile, unit of skin friction and end bearing capacity are accumulated. In our country, the design of piles are made with ASD, however, LRFD considering service, strength and extreme state was adopted in Incheon Grand Bridge implemented with BTL, and the research to systematize the resistance coefficient appropriate at home country are being progressed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.127-130
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• 2017

The information and communication technology that is being developed recently has been greatly influencing the automobile market. In recent years, devices equipped with IT technology have been installed for the safety and convenience of the driver. It is necessary to develop a system that can link the Smartphone with the vehicle in accordance with these changes. In this paper, first of all we analyze the car connectivity services that served by the other competitors. In addition, we proposed and implemented the improved system that can support and control most of smart device application in vehicle by user's NEEDS. We also implemented the application that can restrict the applications which unsatisfied the drive regulations and designed and proposed the scenario that can apply our company's car connectivity system in future.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.6B
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• pp.456-468
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• 2008

In this paper, we design Input/Output modules as a preference work for implementation of hybrid two stage AWG based WDM-PON and verify operations of each function modules through the logic simulation. This WDM-PON system provides service to 128 ONUs through 32 wavelength and one wavelength is shared for upstream transmission with four ONU while each wavelength is allocated to each ONU for downstream transmission. The designed WDM-PON MAC chip is based on sub-MAC which consists of one control unit and reception unit and four transmission unit. To design the reception and transmission unit of sub-MAC, we define the functions of the sub-MAC, pins of the modules, control signal and timing of each signal. We intend to design MAC chip with 1Gbps transmission rate. Thus the designed MAC chip is worked on 125MHz clock rate. We define FSM and design Input/Output modules with VHDL. The logic simulation of the modules is executed by the ModelSIM simulator.

• Journal of Information Processing Systems
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• v.8 no.2
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• pp.347-358
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• 2012

Recently, security researches have been processed on the method to cover a broader range of hacking attacks at the low level in the perspective of hardware. This system security applies not only to individuals' computer systems but also to cloud environments. "Cloud" concerns operations on the web. Therefore it is exposed to a lot of risks and the security of its spaces where data is stored is vulnerable. Accordingly, in order to reduce threat factors to security, the TCG proposed a highly reliable platform based on a semiconductor-chip, the TPM. However, there have been no technologies up to date that enables a real-time visual monitoring of the security status of a PC that is operated based on the TPM. And the TPB has provided the function in a visual method to monitor system status and resources only for the system behavior of a single host. Therefore, this paper will propose a m-TMS (Mobile Trusted Monitoring System) that monitors the trusted state of a computing environment in which a TPM chip-based TPB is mounted and the current status of its system resources in a mobile device environment resulting from the development of network service technology. The m-TMS is provided to users so that system resources of CPU, RAM, and process, which are the monitoring objects in a computer system, may be monitored. Moreover, converting and detouring single entities like a PC or target addresses, which are attack pattern methods that pose a threat to the computer system security, are combined. The branch instruction trace function is monitored using a BiT Profiling tool through which processes attacked or those suspected of being attacked may be traced, thereby enabling users to actively respond.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.2
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• pp.168-180
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• 1992

Commumication technology has been continuously developed to overcome the distance and time for the transmission of information to the human society. Wireless mobile communication, which had been used mostly in the military and police is widely used these days for enterprise and individuals. Therefore the domestic usage of the advanced mobile phone service are progressively gaining wide popularity. The modulation techniques used usually in mobile communications were the analog techniques such as AM and FM, but they are getting replaced by the digital techniques, However, the major disadvantage of the digital communications is the increase of the transmission bandwidth. Therefore, it is very important to use efficiently the limited frequency bandwidth. The domestic research and development on the subject seems quite limited and in order to establish the technology of the digital mobile communications. This thesis presents the design of the frequency hopping synthesizer providing 124 channels with a channel spcing of 200KHz. VCD used in the synthesizer employs a semi-rigid cable for higher purity of signal spectrum, and a hybrid pgase detector is realized with a sample hold phase detector in conjuction with a tri-state phase detedctor.

• Journal of Environmental Health Sciences
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• v.33 no.3
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• pp.184-189
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• 2007

Pathogenic microbial foodborne disease outbreaks (PMFBDOs) have increased in many countries, the boom in food service establishment is not matched by effective food safety and control. In this study, we investigated the current state and the epidemic aspects of FBDOs in Korea and Japan. In Korea, the average prevalence rate of foodborne disease (FBD) was 15.0 per 100,000 population and cases per outbreak of FBD was 57.0. During the same period in Japan, the prevalence rate showed an average of 24.9, and the cases per outbreak were 16. When both prevalence rate and cases per outbreak were compared, the prevalence rate in Japan was much higher than that in Korea (p<0.01). However, average cases per outbreak of FBD in Japan were much lower than those in Korea (p<0.01). In Korea, outbreaks of FBDs were more common in spring (p<0.01), while in Japan, more frequent in summer and winter (p<0.01). Outbreaks of FBD occurred largely through restaurant and school foods (32.0% and 27.5%) in Korea. In Japan, the proportion of the outbreak cases in the restaurant and home were 23.7% and 12.1%, and cases of unknown causes of FBDs were 48.2%, respectively. Bacteria were the major causes of infection in both countries. The prevalence of PMFBDOs by Salmonella spp. Vibrio parahemolyticus and Staphylococcus aureus were much higher in Korea, while those by Camphylobacter spp. and SRSV were more common in Japan. The causes by virus were more frequent in Japan (13.7%) than in Korea (7.7%). The prevalence of FBDs in Korea and Japan showed characteristic differences, especially in the PMFBDOs due to such factors as geography, climate, culture, diet and food management.

• Korean Journal of Agricultural Science
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• v.44 no.1
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• pp.123-132
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• 2017

Nowadays, many people suffer from stress because of their jobs, studies, traffic, etc. Daily stress may cause many diseases (Garrett, 1991). One of the methods for reducing stress is experiencing a natural environment (Frumkin, 2001). Cibodas botanical garden (CBG) is one of the most famous travel destinations in Bogor, Indonesia. CBG has the potential for tourism activities. However, an economic assessment is required to verify their sustainability. The research objectives of this study were to identify the characteristics of tourism utilization in CBG, to analyze the economic tourism value of CBG, and to measure the effectiveness of traveling to a natural environment for reducing stress. The research method used was the survey. This study used three data analysis methods: (1) descriptive analysis which was used to identify the characteristics of tourists, (2) travel cost method (TCM), and (3) contingent valuation method (CVM). Results showed some differences in the characteristics of foreign and domestic tourists respondents in age, educational background, income level, number of dependents, and the frequency of their visits. CBG has a high economic value, amounting to IDR (Indonesian Rupiah) 5,508,932,605,405 or approximately USD (United State Dollar) 413,000,000. WTP (Willingness to Pay) of domestic tourist respondents was IDR 29,702 or USD 2.2 per visit, while the value of foreign tourist respondents reached IDR 39,700 or USD 2.9 per visit. Respondents found it preferable to pay more for tickets (WTP value) than to buy medication to reduce their stress.

• Smart Structures and Systems
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• v.20 no.5
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• pp.619-636
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• 2017

Magnetorheological (MR) damper is a type of controllable device widely used in vibration mitigation. This device is highly nonlinear, and exhibits strongly hysteretic behavior that is dependent on both the motion imposed on the device and the strength of the surrounding electromagnetic field. An accurate model for understanding and predicting the nonlinear damping force of the MR damper is crucial for its control applications. The MR damper models are often identified off-line by conducting regression analysis using data collected under constant voltage. In this study, a MR damper model is integrated with a model for the power supply unit (PSU) to consider the dynamic behavior of the PSU, and then a real-time nonlinear model updating technique is proposed to accurately identify this integrated MR damper model with the efficiency that cannot be offered by off-line methods. The unscented Kalman filter is implemented as the updating algorithm on a cyber-physical model updating platform. Using this platform, the experimental study is conducted to identify MR damper models in real-time, under in-service conditions with time-varying current levels. For comparison purposes, both off-line and real-time updating methods are applied in the experimental study. The results demonstrate that all the updated models can provide good identification accuracy, but the error comparison shows the real-time updated models yield smaller relative errors than the off-line updated model. In addition, the real-time state estimates obtained during the model updating can be used as feedback for potential nonlinear control design for MR dampers.

• Journal of the Korea Safety Management & Science
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• v.17 no.2
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• pp.215-228
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• 2015

A creative innovation and an innovative problem-solving of industrial companies can be achieved by overcoming the challenges of technical and physical contradictions. The approaches to address conflicting and paradoxical problems, such as technical and physical contradictions have a crucial role in advancing the quality assessment for manufacturer and service provider. The term, technical contradiction, depicts the state that improvement of one ends of IFR (Ideal Final Result) leads to unfavorable condition of the other ends, and results in conflicting problem. Another type of contradictions that's discussed in this study is a physical contradiction which is due to two mutually opposing states of the means of ends, and gives paradoxical situation. By integrating the means-ends chain perspectives, the physical contradiction that is a specifically root-causes, "means", can be initially addressed to resolve the downstream problem of technical contradiction which represents a general and abstract goals, "ends". This research suggests IFR resolution processes to handle both physical contradiction of means and technical contradiction of ends by employing causal relationship with IFR, effects and causes. In summary, the study represents three major processes that resolve such contradictions are demonstrated as follows: 1) Derivation of causal and hierarchical relationship among IFR, ends and means by considering CAED (Cause-And-Effect Diagram) and LT (Logic Tree). 2) Identification of causal relationship between physical contradiction and technical contradiction by using TPCT (TRIZ Physical Contradiction Tree) and TCD (Technical Contradiction Diagram). 3) Application of integrated TRIZ principles by classifying 40 inventive principles into 4 general conditions of the separation principle of mutually opposite states in space, in time, based on conditions, and between the parts and the whole. In order to validate the proof of proposed IFR resolution processes, the analysis of the TRIZ case studies from National Quality Circle Contest in the years, 2011 to 2014 have been proposed. The suggested guidelines that are built based on TRIZ principles can uniquely enhance the process of quality innovation and assessment for quality practitioners.