• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.12
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• pp.2968-2974
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• 2014

When lighting has installed indoor, we control lighting using human-detecting sensors for people who pass at night and places that are lack of quantity of light. However, malfunction can be caused by positions of inappropriate sensors, and in the case of passages of big buildings, it is a problem that even after a person pass, light apparatuses are turned on for a long time. In this paper, we propose lighting control system based on location positioning for energy saving that control lighting in accordance with passers's position through indoor location positioning. This system use the fingerprinting technology that is one of the location positioning technologies and RSSI data that is collected by a smart device. Using those, it can turn on only lightings that are included in the positioned location and reduce unnecessary power consumption. As a result of experiment, on condition that four people were existing and illumination was 308 lux, we assured reduction effect of 49 Wh.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.5
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• pp.2375-2393
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• 2016

Key agreement is paramount in secure wireless communications. A promising approach to address key agreement schemes is to extract secure keys from channel characteristics. However, because channels lack randomness, it is difficult for wireless networks with stationary communicating terminals to generate robust keys. In this paper, we propose a Robust Secure Key Agreement (RSKA) scheme from Received Signal Strength (RSS) in stationary wireless networks. In order to mitigate the asymmetry in RSS measurements for communicating parties, the sender and receiver normalize RSS measurements and quantize them into q-bit sequences. They then reshape bit sequences into new l-bit sequences. These bit sequences work as key sources. Rather than extracting the key from the key sources directly, the sender randomly generates a bit sequence as a key and hides it in a promise. This is created from a polynomial constructed on the sender's key source and key. The receiver recovers the key by reconstructing a polynomial from its key source and the promise. Our analysis shows that the shared key generated by our proposed RSKA scheme has features of high randomness and a high bit rate compared to traditional RSS-based key agreement schemes.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.1
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• pp.133-138
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• 2007

As a formal document that expresses a set of security requirements for IT products that meets specific consumer needs in the ISO/IEC 15408(CC, Common Criteria) evaluation, protection profiles are developing by many national agencies and companies recently. Since a protection profile is a criteria for security evaluation when the IT systems and products are introduced, the importance of the protection profile is increasing. However, developing protection profiles are still difficult due to lack of detailed methodology and guidance to analyze security environments or to derive security requirements. In this paper, we analyze foreign instances of developing protection profiles and propose a methodology for deriving security requirements through analyzing the TOE security environment.

• Journal of KIISE:Computing Practices and Letters
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• v.7 no.5
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• pp.539-547
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• 2001

Cluster systems employ high speed interconnection networks and use efficient communication layers to gain high performance and scalability. But the diversity in implementation mechanism among these communication layers causes lack of portability. A solution is to provide communication standard APIs such as MPI. This paper introduces MPI-VMMC: an MPI implementation on VMMC. Though the direct deposit transfer mechanism used in VMMC is not suitable for Send/Recv mechanism used in MPI, the proposed sub-layer laid between MPI and VMMC efficiently translates from one mechanism to the other. We also use the lazy pointer and selective zero-copy transfer technique to gain high performance. The peak performance of MPI-VMMC is 90.7Mbytes/sec, which is about 95% of the base communication layer\`s.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.10C
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• pp.992-1000
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• 2009

Available electric wave resources have been limited than frequency demands that increase with the development of radio communication. According to FCC's (Federal Communication Commission) report, 70% of allocated spectrum was unused. This means that the lack phenomenon of electronic wave resources is ineffectively managed compare with the finiteness of frequency resources. According to the recognition of unused frequency within allocated band, this progress has been investigating to identify the unused TV channel and provide radio communication services. This paper proposed the sensing algorithm that efficiently recognizes the frequency resources which does not use and shares with the licensed user through using the multi-band CIC (Cascaded Integrator Comb) filter based on polyphase filter bank. The simulation results verifies that the proposed scheme can obtain the similar performance of variance and relatively low complexity to the existing scheme.

• Journal of KIISE
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• v.42 no.2
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• pp.264-271
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• 2015

The general way to use a triangulation method is based on PTMP communication between an object and wireless modules in an environment, which is established by more than three wireless modules, to recognize the location of an object. Thus, this method has a problem that the PTMP-based system can only be applied in an environment where the wireless infra is already established. In order to solve this problem, the PTP communication schemes have been proposed but they are insufficient to generalize because they lack specific verification. In this paper, problems of an existed location estimation algorithm based on PTP communication are analyzed, and we propose a location estimation algorithm of a fixed object that satisfyies the condition of a single receiver being substituted to multiple receivers. A location estimation system we designed and implemented using CSS wireless communication modules to evaluate the proposed algorithm. We verify, by experimental results, that the optimum moving interval for the location estimation is 3m in indoor environment of $10m{\times}16m{\times}1m$.

• Electronics and Telecommunications Trends
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• v.38 no.1
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• pp.55-64
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• 2023

Recently, preparations for 6G have led to the increasing interest in integrated or hybrid communication networks considering low-orbit satellite communication networks with terrestrial mobile communication networks. In addition, the demand for frequency allocation for new mobile services from low-orbit small satellites to provide global internet of things (IoT) services is increasing. The operation of such satellites and terrestrial mobile communication networks may inevitably cause interference in adjacent bands and the same band frequency between satellites and terrestrial systems. Focusing on the results of the recent ITU-R WP4C meeting, this study introduces the current status of frequency sharing and interference issues between satellites and terrestrial systems, and frequency allocation issues for new mobile satellite operations. Coexistence and compatibility studies with terrestrial IMT in L band and 2.6 GHz band, operated by Inmassat and India, respectively, and a new frequency allocation study (WRC-23 AI 1.18) are carried out to reflect satellite IoT demand. For the L band, technical requirements have been developed for emission from IMT devices at 1,492 MHz to 1,518 MHz to bands above 1,518 MHz. Related studies in the 2 GHz and 2.6 GHz bands are not discussed due to lack of contributions at the recent meeting. In particular, concerning the WRC-23 agenda 1.18 study on the new frequency allocation method of narrowband mobile satellite work in the Region 1 candidate band 2,010 MHz to 2,025 MHz, Region 2 candidate bands 1,695 MHz to 1,710 MHz, 3,300 MHz to 3,315 MHz, and 3,385 MHz to 3,400 MHz, ITU-R results show no new frequency allocation to narrow mobile satellite services. Given the expected various collaborations between satellites and the terrestrial component are in the future, interference issues between terrestrial IMT and mobile satellite services are similarly expected to continuously increase. Therefore, participation in related studies at ITU-R WP4C and active response to protect terrestrial IMT are necessary to protect domestic radio resources and secure additional frequencies reflecting satellite service use plans.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.3
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• pp.9-21
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• 2017

The purpose of this study is to identify the current situation and actual condition of the video security industry, The research method was based on interviews with twelve specialists, and examined the market trends, the problems of the video security industry, the improvement plan and the government promotion strategy. The problem with the domestic video security industry is that there are the decline in overseas exports and the slowdown in exports to China, insufficient measures to overcome certification barriers due to the strengthening of national certification system, domestic demand growth slowed, expansion of domestic market share of Chinese products, lack of high-tech development of domestic products, lack of expertise in technology development and operation and inadequate legislation for revitalizing the video security industry. The improvement plan is as follows. Need to implement export expansion support policy, need to build tailored response system for each country, need improvement of security related demand creation system, take measures such as domestic industrial protection policy, certification barriers and tariff barriers, induce future core technology to create high added value. The government also needs to actively support human resources development, and induce stabilization of relevant laws and institutions. This study will contribute to the development of related industries by suggesting the development direction of the video security industry.

• Journal of the Korean earth science society
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• v.41 no.3
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• pp.307-319
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• 2020

The purpose of this study was to determine whether there are differences in the verbal interactions of earth science gifted depending on their communications structures and group status in small group activities. To this end, a small group activity was conducted to measure the density of the earth, and 8 small groups were selected, including 4 co-ownership type and 4 monopolistics type groups with different communication structures. And then, the framework was developed for analyzing verbal interactions to compare the differences in characteristics between small groups. The results are as follows. First, regardless of the communication structures, there were showing a simple pingpong-type communication structures for all small groups. Second, negative interactions such as 'restraint', 'command', 'complaint', and 'lack of confidence' predominantly appeared in all small groups. Third, the students in the status of out-lookers in small groups were mainly verbal interactions, such as instructing the other person, acting against the other person's actions, and expressing dissatisfaction with the attitudes and abilities of members. Therefore, teachers should guide students to use higher-level verbal interactions in their group activities in small group activities, and engage in students communication to prevent negative interactions from occurring. The teachers also need to check the level of achievement for students in the status of out-lookers in advance and guide them to participate more actively in small group activities. This study is meaningful in that it can be sued to design teaching and learning to improve students' problem solving and communication skills.

• Journal of Ethics
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• no.75
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• pp.63-98
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• 2009

The Social Conflict Index in Korea is considerably high. In the situation where both parties' interests conflict each other, Korean society has shown immature democracy, which couldn't peacefully resolve the conflict because of the lack of tolerance against the counterparty's position. In terms of upbringing educated citizens, who could democratically communicate with others and approach problems, communication skill training is very important, reducing social costs by extreme conflict. Thus, this paper studied the necessity of communication skills training and its sociopolitical implication through case studies about "Communication and Negotiation" class, which is proceeded under university liberal education. Under current university curriculums, increased liberal education programs, related with speaking, focus on cultivating logical and critical thinking in the main. Based on these thinking skills, "Communication and Negotiation" has important implication in terms of cultivating mindset which resolves conflicts and considers other's position by collaborative and emotional perspectives. In terms of cultivating practical communication skills, this "Communication and Negotiation" class requires the change of teaching skills with various training programs, under students' active participation and feedback in the class exercise for resolving problems. Ultimately, through "Communication and Negotiation" class, and as members of society, students could learn matured citizenship and sense of responsibility by respecting others' position and reasonably resolving conflicts.