• International journal of advanced smart convergence
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• v.13 no.1
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• pp.1-11
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• 2024

Cognitive small cell networks, consisting of macro-cells and small cells, are foreseen as a promising candidate solution to address 5G spectrum scarcity. Recently, many technological issues (such as spectrum sensing, spectrum sharing) related to cognitive small cell networks have been studied, but the common control channel (CCC) establishment problem has been ignored. CCC is an indispensable medium for control message exchange that could have a huge significant on transmitter-receiver handshake, channel access negotiation, topology change, and routing information updates, etc. Therefore, establishing CCC in cognitive small cell networks is a challenging problem. In this paper, we propose a potential game theory-based approach for CCC establishment in cognitive radio networks. We design a utility function and demonstrate that it is an exact potential game with a pure Nash equilibrium. To maintain the common control channel list (CCL), we develop a CCC update algorithm. The simulation results demonstrate that the proposed approach has good convergence. On the other hand, it exhibits good delay and overhead of all networks.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.3
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• pp.39-51
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• 2017

Recently, looking at construction sites with either large or small scale, accidents like collision, fall, etc. occur often. These accidents lead to not only damage of human lives but also serious economic loss. In case of large scale constructions sites, safety management systems are used to reduce industrial accidents. However in construction sites with small scale, those systems cannot be applied due to problems such as lack of compatability and high installation expense. In this case, just by putting on safety gears can also reduce industrial accidents. Therefore, in this paper, a safety management systems that can be used at both large and small scale construction sites is proposed. This safety management system consists of a smart module, a repeater and a gateway, and a monitoring system. The smart module, which is detachable, is attached to a safety helmet. This module transfers the current status of the user to the monitoring system through the repeater and the gateway. The repeater transfers the data received from the smart module to the gateway, and the gateway sends the data from the repeater to the monitoring system. The monitoring system shows the user status to the safety supervisor by displaying the data - temperature, height, intensity of illumination, images - received from the smart module. The safety supervisor can monitor the user status in real-time and take immediate action in case of emergency through this monitoring system.

• Korean Journal of Construction Engineering and Management
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• v.12 no.4
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• pp.59-69
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• 2011

Construction works have become larger and more complex, improving productivity by introducing Information Technology (IT) is pursued. In this circumstance, many different kinds of project management system is being introduced, and various IT technologies are applied such as Personal Digital Assistant (PDA), Bar Code, Radio Frequency Identification (RFID), Web Camera, and so on. However, these kinds of technologies might cause reprocessing of information and ineffectiveness of project because of lack of real time information processing technology or separation between construction sites and management offices. Therefore, this research aims to develop Application that can be applied efficiently for construction material management, by understanding problems of former management system with questionnaires and extracting functions with analysis of requirements. This will be possible to input information automatically, to process and check material information in real time, and to identify the location of necessary material. Then, the problem of separation between construction sites and management offices are solved, and as a result, more efficient management of materials in construction sites will become possible.

• Journal of the Korean Society for Library and Information Science
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• v.44 no.2
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• pp.309-331
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• 2010

In this study, the characteristics and types of 1D, 2D barcodes were examined. It is necessary to provide mobile services by making full use of the advantages of the technologies, such as 1D, 2D barcodes, and RFID, and by complementing the disadvantages of them mutually in Korea. Especially, in a mobile environment where the spread of smart phones and mobile networks are expanding, barcodes and RFID (Radio-Frequency Identification) were analyzed as a very useful information media which is able to connect offline analogue media and online digital media. In addition, library automation systems and the cases of mobile student ID services using barcodes and RFID in Korean libraries were analyzed. The cases of mobile services using barcodes in foreign countries were also analyzed. With these cases, we propose a method to empower mobile services using barcodes in Korean libraries.

• Journal of Advanced Navigation Technology
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• v.17 no.1
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• pp.56-62
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• 2013

Recently with smart phones and tablets, next generation mobile communication systems have supported various multimedia contents services. Thus, multimedia communication systems have been gradually increased compared to voice communication systems. Since the growth of multimedia services has increased users' duration on systems and decreased systems' effectiveness on power, a study on effective usage of power needs to be researched. Furthermore, radio shadow areas under heavy urban environments have generated unnecessary power consumption which reduces the usage duration of power on next generation mobile communication systems. This paper has reviewed the communication network architecture on next generation mobile communication systems and the unnecessary power consumption in radio shadow areas. This paper has also proposed the method of the effective power usage and analyzed the effective power usage on next generation mobile communication systems with simulation.

• The Korean Journal of Food And Nutrition
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• v.29 no.6
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• pp.911-922
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• 2016

This study was conducted to assess the recognition and consumption of meal alone and processed food according to major of college students in Seoul Metropolitan area and Chungcheong province, Republic of Korea. To accomplish this, a survey was conducted to investigate 353 college students (171 food & nutrition majors and 182 non-majors) regarding their general characteristics, dietary behaviors, meal alone issues, and the purchase and consumption of processed food. Most major and non-major students skipped breakfast. The main reason for skipping was not having time. Majors and non-majors put great importance on their lunch and evening meal, respectively. Nutrition information routes for majors were 'college class' (62.5%) and 'TV radio' (17.5%). However, the routes for non-majors to obtain nutrition information were 'internet smart phones' (41.1%) and 'TV radio' (28.3%). These results suggest the need to provide correct information concerning nutrition to college students. Most major and non-major students tend to have 0 to 2 times of meal alone per week. The main reason for meal alone was schedule unsuitable for eating with family or friends. The most critical factors for majors and non-majors when they chose menu to have meal alone were personal taste and money, respectively. The primary consideration for choosing processed food was price and the main purchase route was convenience store. The main reason for consuming processed food was easy-to-cook. Of processed foods, the most favored ones were noodles and fish products. Meal alone frequency was positively correlated with age (p<0.05), grade (p<0.05) and monthly allowance (p<0.05). Preference and consumption frequency of processed food were negatively correlated with concern about nutrition (p<0.05) and meal frequency (p<0.05), respectively. Based on these results, greater efforts should be made to provide meaningful information regarding programs for nutrition education to improve their dietary habits. Research and development of processed food specifically for college students eating alone should be increased.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.10
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• pp.1994-2000
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• 2016

Technology that can determine the location of individuals is required in a variety of applications such as location based control, a personalized advertising. Missing-child prevention and support for field trips, and applications such as push events based on the user's location is endless. In particular, the technology that can determine the location without interruption in the indoor and outdoor spaces have been studied a lot recently. Because emphasizing on accuracy of the positioning, many conventional research have constraints such as using of additional sensing devices or special mounting devices. The algorithm proposed in this paper has the purpose of performing the positioning only with standard equipment of the smart phone that has the most users. In this paper, sensor Fusion with GPS, WiFi Radio Map, Accelerometer sensor and Particle Filter algorithm is designed and implemented. Experimental results of this algorithm shows superior performance than the other compared algorithm. This could confirm the possibility of using proposed algorithm on actual environment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.7B
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• pp.586-594
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• 2012

The drastic growth of mobile communication and spreading of smart phone make the significant attention on Location Based Service. The one of most important things for vitalization of LBS is the accurate estimating position for mobile object. Focusing on AP's probabilistic position estimation, we develop an AP distribution map and new pattern matching algorithm for position estimation. The developed approaches can strengthen the advantages of Radio fingerprint based Wi-Fi Positioning System, especiall on the algorithms and data handling. Compared on the existing approaches of fingerprint pattern matching algorithm, we achieve the comparable higher performance on both of average error of estimation and deviation of errors. Furthermore all fingerprint data have been harvested from the actual measurement of radio fingerprint of Seoul, Kangnam area. This can approve the practical usefulness of proposed methodology.

• Smart Structures and Systems
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• v.6 no.5_6
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• pp.675-687
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• 2010

Structural Health Monitoring (SHM) is the science and technology of monitoring and assessing the condition of aerospace, civil and mechanical infrastructures using a sensing system integrated into the structure. Impedance-based SHM measures impedance of a structure using a PZT (Lead Zirconate Titanate) patch. This paper presents a low-power wireless autonomous and active SHM node called Autonomous SHM Sensor 2 (ASN-2), which is based on the impedance method. In this study, we incorporated three methods to save power. First, entire data processing is performed on-board, which minimizes radio transmission time. Considering that the radio of a wireless sensor node consumes the highest power among all modules, reduction of the transmission time saves substantial power. Second, a rectangular pulse train is used to excite a PZT patch instead of a sinusoidal wave. This eliminates a digital-to-analog converter and reduces the memory space. Third, ASN-2 senses the phase of the response signal instead of the magnitude. Sensing the phase of the signal eliminates an analog-to-digital converter and Fast Fourier Transform operation, which not only saves power, but also enables us to use a low-end low-power processor. Our SHM sensor node ASN-2 is implemented using a TI MSP430 microcontroller evaluation board. A cluster of ASN-2 nodes forms a wireless network. Each node wakes up at a predetermined interval, such as once in four hours, performs an SHM operation, reports the result to the central node wirelessly, and returns to sleep. The power consumption of our ASN-2 is 0.15 mW during the inactive mode and 18 mW during the active mode. Each SHM operation takes about 13 seconds to consume 236 mJ. When our ASN-2 operates once in every four hours, it is estimated to run for about 2.5 years with two AAA-size batteries ignoring the internal battery leakage.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.6
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• pp.57-68
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• 2004

Recently, Radio Frequency Identification (RFID) systems stands in the spotlight of industry as a common and useful tool in manufacturing, supply chain management (SCM) and stock management. In the near future, low-cost RFID Electronic Product Code; (EPC) or smart-labels may be a practical replacement for optical barcodes on consumer items. However, manufacturing cheap and small RFID tags, and developing secure RFID authentication Protocols are problems which need to be solved. In spite of advances in semiconductor technology, computation and storage ability of the tag are so limited that it is difficult and too expensive to apply existing crypto-systems to RFID tags. Thus it is necessary to create a new protocol which would require less storage space and lower computation costs and that is secure in the RFID system's environments. In this paper, we propose a RFID authentication protocol that is secure against location tracking and spoofing attacks. Our protocol can be used as a practical solution for privacy protection because it requires less computations in database than the previous RFID authentication protocol.