• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.2B
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• pp.148-158
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• 2011

Stationary nodes and mobile nodes co-exist wireless sensor network(WSN) can provide variety of new services. The stationary sensor node acts not only the gathering the environmental sensing data but also a access point to bidirectional communication with numerous mobile sensor nodes(mobile node), and the mobile sensor nodes are installed inside mobile objects and identify the location in real-time and monitor the internal status of the object. However, only using the legacy WSN protocol, it is impossible to set up the stable network due to the several reasons caused by the free-mobility of the mobile nodes. In this paper, we suggest three methods to increase the hit-ratio of the asynchronous message delivery(AMD) among mobile nodes. We verified the performance of the suggested methods under the stationary-mobile co-existed WSN testbed.

• Journal of Chest Surgery
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• v.24 no.3
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• pp.310-321
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• 1991

Between April 1986 and September 1990, 34 patients with a single or dominant right ventricle underwent modified Fontan procedure for definite palliation in Seoul National University Children`s Hospital. Their age at operation ranged from 8 months to 14 years [Mean 5.5 years]. The ventricular chamber was solitary and of indeterminate trabecular pattern in 6 patients. 28 patients had posteriorly located rudimentary chamber, all of which were trabecular pouches having no communication with outlet septum. The patterns of atrioventricular connection were common inlet[9], double inlet [11], left atrioventricular valve atresia [12] and right atrioventricular valve atresia with L-loop [2]. Pulmonary outflow tracts were atretic in 7 patients and stenotic in 26 patients. Major associated anomalies included anomalous systemic venous drainage [15], dextrocardia [12] and total anomalous pulmonary venous connection[3]. Shunt operations were previously performed in 13 patients and pulmonary artery banding and atrial septectomy in 1 patients. Surgery included intraatrial baffling in 26 patients, bidirectional cavopulmonary shunt in 13 patients, atrioventricular valve obliteration in 3 patients and atrioventricular valve replacement in 3 patients. Central venous pressure measured postoperatively at intensive care unit ranged from 18cm H2O to 28cm H2O [mean 23.2cm H2O]. Hospital mortality was 35.3% [12/34], all died out of low output syndrome. Suspected causes of low output syndrome include ventricular dysfunction [8], hypoplastic or tortuous pulmonary artery [2] and elevated pulmonary vascular resistance [2]. 19 patients had 31 major complications including low output syndrome [18], arrhythmia [4], acute renal failure [3] and respiratory failure [3]. Mortality rate was significantly higher in the groups receiving intraatrial baffling and AV valve replacement respectively [p<0.05]. 20 patients were followed up postoperatively with the mean follow-up period 15.0$\pm$11.6 months. There were no late death and follow-up catheterization was performed in 10 patients. Mean right atrial pressure was 15.4$\pm$6.8mmHg and ventricular contraction was reasonable in all but one case. Thus, Fontan principle can be applied successfully to all the patients with complex cardiac anomaly of single ventricle variety and better results can be anticipated with judicious selection of patient and improvement of postoperative care.

• Imaging Science in Dentistry
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• v.46 no.3
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• pp.211-216
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• 2016

Purpose: The use of electronic tools in teaching is growing rapidly in all fields, and there are many options to choose from. We present one such platform, Learning Catalytics$^{TM}$ (LC) (Pearson, New York, NY, USA), which we utilized in our oral and maxillofacial radiology course for second-year dental students. Materials and Methods: The aim of our study was to assess the correlation between students' performance on course exams and self-assessment LC quizzes. The performance of 354 predoctoral dental students from 2 consecutive classes on the course exams and LC quizzes was assessed to identify correlations using the Spearman rank correlation test. The first class was given in-class LC quizzes that were graded for accuracy. The second class was given out-of-class quizzes that were treated as online self-assessment exercises. The grading in the self-assessment exercises was for participation only and not accuracy. All quizzes were scheduled 1-2 weeks before the course examinations. Results: A positive but weak correlation was found between the overall quiz scores and exam scores when the two classes were combined (P<0.0001). A positive but weak correlation was likewise found between students' performance on exams and on in-class LC quizzes (class of 2016) (P<0.0001) as well as on exams and online LC quizzes (class of 2017) (P<0.0001). Conclusion: It is not just the introduction of technological tools that impacts learning, but also their use in enabling an interactive learning environment. The LC platform provides an excellent technological tool for enhancing learning by improving bidirectional communication in a learning environment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.1
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• pp.61-71
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• 2017

ARP Spoofing is a basic and core hacking technology for almost all sniffing. It makes change the flow of packets by faking the 2nd layer MAC address. In this paper we suggested an efficient hacking technology for sniffing remote servers in the switched network environment. The suggested 'Faked ARP Reply Unicast Spoofing' makes the bidirectional packets sniffing possible between the client and server, and it makes simplify the procedures for ARP sniffing and hacking program. In this paper we researched the network hacking and implementation technologies based on the suggested ARP spoofing. And we researched various types of servers hacking such as Root ID and PW of Telnet/FTP server, Root ID and PW of MySQL DB server, ID and PW of Web Portal Server, and account information and transaction history of Web Banking Server. And also we researched the implementation techniques of core hacking programs for the ARP Spoofing.

• Journal of the Korea Fashion and Costume Design Association
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• v.16 no.3
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• pp.33-48
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• 2014

Based on the advent and dissemination of new developments concerning information & telecommunications technology, web services have brought new paradigms into society, thus facilitating the birth and evolution of various service industries to society as a whole. This study is aimed at investigating the expansion of the first Birthday party culture and design examples of the first Birthday partywear appearing in social media, through an inquiry into the communication functions inherent in social media. Also, the development of the first Birthday partywear designs for women aged 20 to 30 years was accomplished by categorically analyzing design characteristics in preferred fashion styles uploaded and shared within online childcare communities. First, it can be concluded that due to the bidirectional flow of information between corporations and consumers occurring from the expansion of social media, the entire structure of the market is undergoing great changes. Next, the need for the supply of professionalized the first Birthday partywear can be proved by the influx of party planners and caterers into this new industry. Third, Through a categorical analysis of these 523 photos, elegance style was the most preferred while classic and romantic styles followed. Last of all, 5 pieces of partywear reflecting contemporary consumer lifestyles which focus on 'enjoying one's own life' were created under the concept of 'Romantic chic'. The created designs aim to present a style which follows the predominant trend of elegance, classic and romantic, whilst keeping sensitivity in moderation. In this context, this study has aimed to present fundamental research data in the field of online the first Birthday partywear, through the development of the first Birthday partywear design based on the first Birthday party consumer characteristics gleaned from various forms of social media.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.1_2
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• pp.110-118
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• 2006

Cryptographic protocol design in a two-party setting has of tel ignored the possibility of simultaneous message transmission by each of the two parties (i.e., using a duplex channel). In particular, most protocols for two-party key exchange have been designed assuming that parties alternate sending their messages (i.e., assuming a bidirectional half-duplex channel). However, by taking advantage of the communication characteristics of the network it may be possible to design protocols with improved latency. This is the focus of the present work. We present three provably-secure protocols for two-party authenticated key exchange (AKE) which require only a single round. Our first, most efficient protocol provides key independence but not forward secrecy. Our second scheme additionally provides forward secrecy but requires some additional computation. Security of these two protocols is analyzed in the random oracle model. Our final protocol provides the same strong security guarantees as our second protocol, but is proven secure in the standard model. This scheme is only slightly less efficient (from a computational perspective) than the previous ones. Our work provides the first provably- secure one-round protocols for two-party AKE which achieve forward secrecy.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.5
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• pp.1105-1110
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• 2011

It is possible to synchronize the spatio-temporal data with a server using a wireless network. These data has the benefit to be up-to-date and able to service to the user efficiently. However, the mobile devices or the wireless network are very vulnerable to various hard or soft failures. If an failure occurs during a synchronization process, the spatio-temporal data which is synchronizing could be inconsistent state. In this paper, we propose the recovery scheme to solve the problem caused by the errors which occur during the synchronization on mobile environments. The proposed scheme writes the log records for the synchronization process into the both local storages of the server and the mobile client. When the errors arise, the data which are synchronizing are recovered using the written log records. Also, we design and implement the proposed recovery scheme on the synchronization system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.12B
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• pp.1115-1123
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• 2003

In this paper, a remote control system called TeleRemote system which can be applied to existing wireless mobile networks or public telephone networks for remote control is designed and implemented. The proposed design employs program technology based on the theory of signal detect control and enables the EPG(Electronic Program Guide) functions such as recording reservation of bidirectional video signals with TV reception card on PC. It can also control recording reservation using remote control program through telecommunication network The PC-EPG system is implemented in Web programs with Server/Clinet architecture and the server system that provides EPG functionalities is in charge of recording reservations and data communications by means of the scheduler program. Data storing to client PCs is performed through TCP/IP and finished by client programs implemented using Visual C++/MFC programs. As remote control system, the developed system can be used for unmanned security system using the Web camera. Building intranet and making connection to internet, the TeleRemote system is believed to create potential for commercial communication system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.3
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• pp.427-437
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• 2008

In order to increase the coupling efficiency of the power and phase of the active phase array antenna, we have fabricated the active phased-array antenna which is coupled by the transmission line, and investigated the relationship between the length of the coupling transmission line and coupling power and phase. The following three types of driving method - (1) giving the frequency difference between the two active antenna, (2) applying the input signal to the one side of the two antennas, and changing the eigen frequency of the other side antenna, (3) appling the different phase inputs to the active antennas was investigated. The experimental results showed that the interval of the antenna elements has not affected the power and the phase of the antenna.

• Korean Journal of Remote Sensing
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• v.35 no.1
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• pp.57-81
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• 2019

Satellite images can be integrated into a crop model to strengthen the advantages of each technique for crop monitoring and to compensate for weaknesses of each other, which can be systematically applied for monitoring inaccessible croplands. The objective of this study was to outline the productivity of paddy rice based on simulation of the yield of all paddy fields in North Korea, using a grid crop model combined with optical satellite imagery. The grid GRAMI-rice model was used to simulate paddy rice yields for inaccessible North Korea based on the bidirectional reflectance distribution function-adjusted vegetation indices (VIs) and the solar insolation. VIs and solar insolation for the model simulation were obtained from the Geostationary Ocean Color Imager (GOCI) and the Meteorological Imager (MI) sensors of the Communication Ocean and Meteorological Satellite (COMS). Reanalysis data of air temperature were achieved from the Korea Local Analysis and Prediction System (KLAPS). Study results showed that the yields of paddy rice were reproduced with a statistically significant range of accuracy. The regional characteristics of crops for all of the sites in North Korea were successfully defined into four clusters through a spatial analysis using the K-means clustering approach. The current study has demonstrated the potential effectiveness of characterization of crop productivity based on incorporation of a crop model with satellite images, which is a proven consistent technique for monitoring of crop productivity in inaccessible regions.