• Journal of Web Engineering
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• v.19 no.1
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• pp.29-62
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• 2020

In highly dynamic IoT environments, the connection statuses of IoT resources and the availability of IoT-based services change frequently. Therefore, to successfully build distributed service registries for managing and finding the information about available services in an effective manner, it is crucial to minimize the overhead of message exchanges between registries and to reduce the time overhead for identifying the capabilities of available IoT resources and the services that can be provided by utilizing these capabilities. In this paper, we propose a lightweight messaging approach that uses hierarchical Bloom filters to efficiently represent service information to be exchanged and managed by distributed service registries for IoT environments with high mobility. We also propose a method for serializing the dimensions of a Bloom-filter-encoded search space. We conducted experiments to demonstrate the improvement in the service discovery performance, the reduction in message traffic among service registries, and the decrease in the latency when synchronizing distributed service registries.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.4
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• pp.63-72
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• 2010

This paper proposes a new authentication protocol for the LR-WPAN. In order to guarantee the reliability and safety of a protocol, this protocol uses the hierarchical authentication approach. In addition, in order to reduce the impact of the denial of service attack, the proposed protocol performs the authentication between a parent router and a joiner device prior to the authentication between a trust center and the joiner device. Moreover, this protocol reduces the authentication delay by decreasing the number of message exchanges during authentication procedure. This paper evaluates the safety of the proposed protocol by the security analysis and reliability of the proposed protocol by the GNY analysis. This paper also compares the number of message exchanges of the ZigBee authentication protocol and the proposed protocol when denial of service attack occurs to evaluate the resistance of the proposed protocol against the denial of service attack. We also analyze the delay for authentication of the joiner device through the implementation of both protocols. Those results show that the proposed protocol effectively protects networks from the denial of service attack and reduces the time for authenticating the joiner device up to maximum 30% as the number of hops increases.

• Journal of Internet Computing and Services
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• v.19 no.5
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• pp.89-96
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• 2018

In online communities, a large number of participants can exchange their opinion using replies without time and space restrictions. While the online space provides quick and free communication, it also easily triggers unnecessary quarrels and conflicts. The network established on the discussion participants is an important cue to analyze the confrontation and predict serious disputes. In this paper, we present a quantitative measure for polarity observed on the discussion network built from reply exchanges in online communities. The proposed method uses the comment exchange information to establish the user interaction network graph, computes its maximum spanning tree, and then performs vertex coloring to assign two colors to each node in order to divide the discussion participants into two subsets. Using the proportion of the comment exchanges across the partitioned user subsets, we compute the polarity measure, and quantify how discussion participants are bipolarized. Using experimental results, we demonstrate the effectiveness of our method for detecting polarization and show participants of a specific discussion subject tend to be divided into two camps when they debate.

• The Journal of Korean Philosophical History
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• no.58
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• pp.337-356
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• 2018

Zhangshi established his own ideal system in the process of self-cultivation in the Southern Song dynasty period, where academic exchanges were active. A common feature in the process of self-cultivation is the transformation of ideas. In the case of Zhangshi, his academic exchanges with contemporary mainstream scholars had a major impact on them, and Zhangshi was also able to systematize his own ideas. However, while there have been a lot of researches on the mainstream schools of the Southern Song period, there has been little research on the ideological trends and trends of the time when mainstream schools could have occurred. This paper attempts to understand the ideological trends of the Southern Song era by examining the formation process of the his theory of self-cultivation, and to examine the process of exchanging of mainstream schools through the field of self-cultivation. This work will be a meaningful process for understanding the philosophy of the Song era and for examining the tendency objectively. This paper examines the formation process of self-cultivation in the first half and the second half. In the first half, this paper refers to the ideological impact of schools that had influenced Zhangshi's thought, in the second half, this paper deals with the process of change of his theory of self-cultivation and then examines how his ideas had changed. This work will help to understand Zhangshi's own ideas and to understand how Zhu Xi's theory of Zhu xi, who had an ideological exchange with him, could be established.

• The Southeast Asian review
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• v.21 no.2
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• pp.77-123
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• 2011

Recently, Southeast Asian people, its food, natural sceneries and so on have been increasingly exposed to Korean people through mass media and multi-cultural events. At the same time, Koreans can frequently encounter Southeast Asians in their everyday lives. Thus, specific images and discourses of Southeast Asia has been established in our society, which creates a new social trend called 'Southeast Asia phenomena'. In short, 'Southeast Asia phenomena' means a totality of Korean people's experience of Southeast Asian and their perception on the region. On the one hand, 'Southeast Asia phenomena' is a result of inflow of Southeast Asians and their culture into Korea. On the other hand, it is also a consequence of Korean people's understanding of Southeast Asia from their trip to Southeast Asia or from their interactions with Southeast Asian people. This article aims to analyze the origin and diffusion of 'Southeast Asian Phenomena' in Korea in the context of Southeast Asia focusing on 4 topics, that is, migrant workers, overseas investments, retirement migration, study-abroad categorized as human movement. This article is also about a country-by-country comparative analysis both at the macro level and the micro level. At the macro level, overseas investments and trade, human exchanges, positive perception to Koreans which considered to be the structural causes become a strong mechanism playing a important bridge role between Korea and Southeast Asia. So these create the high probability of the emergence of 'Southeast Asian Phenomena' At the micro level which is more direct causes of 'Southeast Asian Phenomena', the economic cause is the most important common cause for 4 Southeast Asian Phenomena. Additionally, Korean wave is also remarkable common cause creating 'Southeast Asian Phenomena' even it is not the origin in the context of Southeast Asia. The diffusion of 'Southeast Asian Phenomena' is different by the topics and the elements contributing to create the favorable situation for the diffusion are not only overseas investments and trade, human exchanges at the macro level but also policy elements at the micro level. The relative differences of the causes of 'Southeast Asian Phenomena' in the country-by-country analysis are found. Regarding overseas investments in Vietnam and Cambodia, the economic degree of freedom in Cambodia is higher than in Vietnam. Even Korean Wave has had the longer history in Vietnam, but the favorable perspectives on Korean Wave are stronger in Cambodia. For migrant workers from Vietnam and Indonesia, the economic causes in Vietnam are more significant than in Indonesia. The impact of Korean Wave is stronger in Vietnam than in Indonesia. In case of study-abroad, the social-cultural elements and policy elements are more diverse in Malaysia than in Korea. For the Korean retirees who immigrate to the Philippines and Malaysia, the economic causes in the Philippines is more significant in Malaysia.

• (The)Study of the Eastern Classic
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• no.59
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• pp.157-181
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• 2015

This thesis pursued exchanges of Hwangsang with Chusa Family, who existed in the 19th century. What was Chusa to Hwangsang and what was Hwangsang to Chusa? The answer is concluded to the question of which existence Chusa was to Hwangsang but not of which existence Hwangsang was to Chusa. However, disregarding social positions of the nobles and the commoners, brothers of Chusa also cherished Hwangsang and respectfully treated him as a poet at all times. Chusa was a critic who recognized Hwangsang as a successor to Dasan poetics and became a patron of the literary circles on the other hand. Hwangsang's Chinese poems related to Chusa Family are counted as 45 JE 52 SU in total which consist of 31 JE 34 SU in "CHIWONYUGO" and 14 JE 18 SU in "CHIWONSOGO", On the other hand, Chinese poems which Chusa wrote for Hwangsang are only a few pieces shown in "WANDANGJEONJIP". Hwangsang first met three brothers including Chusa in September 1853 when he came up to the capital for the 4th time. Jeong Hak-yeon, the oldest son of Dasan Jeang Yak-yong, played an important role in the whole process that Hwangsang met Chusa's three brothers and was recognized as a poet. As the oldest son of Dasan Family, Jeong Hak-yeon made efforts in various ways for Hwangsang. Hwangsang tried his efforts to exhibit his ability as a poet to Chusa and to get Chusa's introduction of his poetical works. Considering Chusa's importance in then literary circles, the introduction seemed to reflect recognition by the literary circles in the metropolis and it also showed that Hwangsang was no more than an obscure poet in the provincial area. Poetical composition of Hwangsang for Chusa three brothers commonly contained friendship, intimacy and special respect at all times. Seeing from exchange process between Hwangsang and Dasan Family or Chusa Family, it is found that mutual exchanges were actively made in the mid-nineteenth century overcoming regional differentiation between capital and province, or feudalism class distinction of social positions of the nobles and the commoners.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.5
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• pp.10-18
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• 2017

The problem of non-ideal detonation propagation velocities in heterogeneous hybrid mixtures is studied in the case of a high explosive with suspended fine aluminum (Al) particles. Since there exist difference in the time scales of the characteristic induction and combustion of High Explosives and solid particles, the process of energy release behind the leading shock front occurs over an extended period of time. The problem is analyzed by the theory of the mechanics of multiphase media with mass, momentum and heat exchanges between particles and gases. The numerical results match the available experimental results of heavily aluminized (5~25% Al weight) HMX explosive obtained previously.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.8
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• pp.1789-1798
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• 2012

IEEE 802.15.4a standard can provide a variety of location-based services for ZigBee or wireless network applications by adapting the time-of-arrival (TOA) ranging technique. The non-line-of-sight (NLOS) condition is the critical problem in the IEEE 802.15.4a networks, and it can significantly degrade the performance of the TOA-based localization. To enhance the location accuracy due to the NLOS problem, this paper proposes an energy-efficient low complexity localization algorithm. The proposed approach performs the ranging with the multicast method, which can reduce the message overhead due to packet exchanges. By limiting the search region for the location of the node, the proposed approach can enhance the location accuracy. Experimental results show that the proposed algorithm outperforms previous algorithms in terms of the energy consumption and the localization accuracy.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.5C
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• pp.726-736
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• 2004

In this paper, we proposed a new scalar multiplier structure needed for an elliptic curve cryptosystem(ECC) over the standard basis in GF(2$^{163}$ ). It consists of a bit-serial multiplier and a divider with control logics, and the divider consumes most of the processing time. To speed up the division processing, we developed a new division algorithm based on the extended Euclid algorithm. Dynamic data dependency of the Euclid algorithm has been transformed to static and fixed data flow by a localization technique, to make it independent of the input and field polynomial. Compared to other existing scalar multipliers, the new scalar multiplier requires smaller gate counts with improved processor performance. It has been synthesized using Samsung 0.18 um CMOS technology, and the maximum operating frequency is estimated 250 MHz. The resulting performance is 148 kbps, that is, it takes 1.1 msec to process a 163-bit data frame. We assure that this performance is enough to be used for digital signature, encryption/decryption, and key exchanges in real time environments.

• Industry Promotion Research
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• v.5 no.1
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• pp.157-164
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• 2020

After the Qing Dynasty overthrow of the Ming dynasty, this is far-reaching influenced on the Ming Dynasty's Sovereign state of the Joseon dynasty. Not only did regulations prohibit the entry into various books published by the Qing Dynasty, In addition, the "Northern Expedition" of Song Siyeo put forward the mainstream political proposal of the Northern Expedition and Qing Dynasty.Even in this context, Representatives of scholars such as Hong Daeyong, Bak Jega, Kim Jeonghui on the Joseon dynasty peninsula at the time, put forward the idea of "Learning from Central Plains" through several visits to Shuntian Prefecture (now Beijing), And gradually formed the well-known Silhak (Practical Learning) ideological of "Bukhak, (Northern Learning)" in the Joseon dynasty history. the Joseon dynasty Silhak ideological scholar of Kim Jeonghui also was under the influence of the Weng Fanggang and Ruan yuan other famous Qing Dynasty Textual scholar, Fruitful achievements in Chinese Classical Studies Epigraphy, Calligraphy.He founded the "Chusa-che" style of calligraphy Chusa, the "Chusa-che" styled is although born out of the clerical script, but more composition and See also asymmetrical in harmony, Strong and vigorous brush strokes, Every word vibrant, Make it a master of gold stone calligraphy in the Joseon Dynasty.This study based on some records of Kim Jeonghui's visited to Shuntian Prefecture(now Beijing), this article examines the academic activities of seeking truth to facts in Korea and the Qing Dynasty at the time, and the impact on these activities on calligraphy and painting in the Joseon Dynasty.