• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.6
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• pp.1117-1124
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• 2023

The security of information, including image content, is an essential part of today's communications technology and is critical to secure transmission. In this paper, a new ROI-based image encryption algorithm is proposed that can quickly encrypt images with a security level suitable for environments that require real-time data transmission for images containing sensitive information such as ID cards. The proposed algorithm is based on one dimensional 5-neighbor cellular automata, which can be implemented in hardware and performed hardware-friendly operations. Various experiments and analyses are performed to verify whether the proposed encryption algorithm is safe from various brute-force attacks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.8C
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• pp.1125-1132
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• 2004

In this Paper, we Propose an effective boundary matching based error detection algorithm using causal neighbor blocks to improve video quality degraded from channel error in block-coded video. The proposed algorithm first calculates boundary mismatch powers between a current block and each of its causal neighbor blocks. It then decides that a current block should be normal if all the mismatch powers are less than an adaptive threshold, which is adaptively determined using the statistics of the two adjacent blocks. In some experiments under the environment of 16bi1s burst error at bit error rates (BERs) of 10$^{-3}$ -10$^{-4}$ , it is shown that the proposed algorithm yields the improvements of maximum 20% in error detection rate and of maximum 3.5㏈ in PSNR of concealed kames, compared with Zeng's error detection algorithm.

• Journal of Advanced Navigation Technology
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• v.11 no.4
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• pp.415-422
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• 2007

In this paper, we proposed a new dynamic channel allocation algorithm for TD-SCDMA with cross time slots. In order to reduce the interference in cross time slot, the mobile stations (MSs) are divided into two groups: the Near Group consisting of MSs near by the base station(BS) and the Far Group including the MSs far from the BS. The reverse link for MSs in the Near Group and forward link for MSs in the Far Group are allocated to the cross time slot. In cellular systems, a BS has multiple neighbor BSs. Some of neighbor BSs can operate in the same direction link while the others have cross time slot. Thus, it is required to determine which BS has the most significant impact in terms of interference. We divide each cell into 6 areas based on the direction of arrival of smart antenna and the most significant neighbor sector is determined with this division. The proposed allocation method and area division method can avoid the severe interference in cross time slots and increase the system capacity about 2%~9% compared to FCA, and 0.5%~1.3% compared to RCA.

• Journal of KIISE:Information Networking
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• v.37 no.1
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• pp.1-7
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• 2010

Network Centric Warfare(NCW) is becoming a prominent concept in the current trend of warfare. To support high quality communication between strategic/tactical units in the concept of NCW, Tactical Airborne Networks are likely to be constructed in the near future to take part in the NCW. In these Tactical Airborne Networks with dynamic topology variations due to very high mobility of participants nodes, more efficient and reliable neighbor discovery protocols are needed. This paper presents the adaptive HELLO message scheduling algorithm for Tactical Airborne Network using directional antennas. The purposed algorithm can reduce the overhead of periodic HELLO message transfer, while guaranteeing successful data transmission. We concluded a mathematical analysis and simulation studies using Qualnet 4.5 for evaluation the performance and efficiency of the proposed scheme.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.3 s.94
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• pp.327-334
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• 2005

In this paper, a new PAPR reduction method using correlation of input data sequence is proposed in order to overcome the serious drawbacks, such as necessity of side information transmission or increase of system complexity and calculation which are the basis of previous SLM, PTS and DSI method. A new PAPR reduction method can be classified into Method 1 and Method 2. Method 1 reduces the correlation between the smallest sub-sequence and neighbor smallest sub-sequence. And, to consider the own correlation in detail, the Method 2 reduces two case of correlation between neighbor smallest sub-sequences and neighbor largest sub-sequences. According to simulation result, Method 1 and Method 2 has about 0.5 $\~$ O.8 dB and 1 $\~$ l.2 dB PAPR reduction effect respectively. If more detailed process to reduce the correlation of input data sequence is considered, we can achieve better PAPR reduction performance.

• The Korean Journal of Applied Statistics
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• v.32 no.5
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• pp.671-681
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• 2019

Studies on predicting arrhythmia using machine learning have been actively conducted with increasing number of arrhythmia patients. Existing studies have predicted arrhythmia based on multivariate data of feature variables extracted from RR interval data at a specific time point. In this study, we consider that the pattern of the heart state changes with time can be important information for the arrhythmia prediction. Therefore, we investigate the usefulness of predicting the arrhythmia with multivariate time series data obtained by extracting and accumulating the multivariate vectors of the feature variables at various time points. When considering 1-nearest neighbor classification method and its ensemble for comparison, it is confirmed that the multivariate time series data based method can have better classification performance than the multivariate data based method if we select an appropriate time series distance function.

• Korean Journal of Adult Nursing
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• v.17 no.1
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• pp.3-11
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• 2005

Purpose: This study was conducted to investigate quality of life according to social support of elderly in the rural area. Method: The subjects of this study were 199 people aged over 60 who had been living in three rural areas. Date was collected through questionnaires from July 10th, to August 10th, 2003. Result: The most socially supportive people they answered were friends(80.9%), followed by children(74.9%), neighbors(71.9%), siblings(55.8%), spouse(53.3%), in descending order. Mean social support score for spouse was 13.36, for children 13.27, for friends 11.40, for neighbors 10.21, for siblings 10.20. A comparison of the average grade points per items according to the offerers of social support revealed spouse support(13.36 out of 18), children support(13.27), friends support(11.40), neighbor support(10.21), siblings support(10.20). The average of the quality of life score was 132.26 out of 220. A comparison of the average grade points per items within sub-areas of quality of life revealed the highest score of neighbor relationships(4.29 out of 5.00) and the lowest score of economic conditions (2.61) Quality of life scores correlated positively with social support scores(r=.734, p<.001). Variables significantly influencing quality of life were spouse support(36.1%), neighbor support (5.1%), age(2.2%), religion(1.7%). These variables explained 45.1% of the variance in quality of life. Conclusion: Social support for elderly people in rural areas identified this as a greatly effective factor for their quality of life. Therefore, it is necessary to develop health promotion programs connected with social support in order to enhance the quality of elderly people in rural areas.

• Journal of Korea Society of Industrial Information Systems
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• v.20 no.5
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• pp.25-35
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• 2015

Handoff is a critical issue for seamless roaming in IEEE 802.11-based wireless networks. In order to provide real-time services, handoff mechanism must be provided. However, the IEEE 802.11 standard handoff is not appropriate to provide the services, because it is based on the full-scanning approach which spends too much time searching Access Point (AP). In this paper, we propose a new scheme, which can reduce the scanning latency. A station performs full-scanning operation for finding APs when it enters wireless networks for the first time. The station sends the scanned channel information to AP. AP maintains the neighbor channel table based on the information received from stations. A station performs the partial-scanning by using the table. Therefore, the proposed scheme can reduce the scanning latency.

• The Journal of Society for e-Business Studies
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• v.17 no.2
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• pp.115-127
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• 2012

The diffusion of the mobile telecommunication service in a country could be affected by the diffusions of the services in her neighbor countries. Previous studies on the diffusions of the telecommunication service among countries have been mainly focussed on the comparison after individual diffusion estimation. However, it would be natural to think the diffusion of the mobile telecommunication service in one country could affect to and be affected by the diffusion of the mobile telecommunication service in her neighbor country. In this study, we have applied the multinational diffusion model to model the crossnational effect in the diffusion of the mobile communication service in China, Korea, U.S., Japan, and Hong Kong. Among these 5 countries China is the latest country to adopt the mobile communication service, and we were interested in whether the diffusion of the mobile communication service in Korea, U.S., Japan, or Hong Kong has affected the diffusion of the mobile communication service in China or not. In our application result, the diffusion of the mobile communication service in China has been affected significantly by those in all of the 4 neighbor countries.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.29 no.3
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• pp.41-63
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• 2018

This study aimed at analyzing journals and index terms, authors of the reformed theology and evangelicalism, neutral theological position by using bibliometrical analyzing methods. The analyzing methods are average linkage and neighbor centralities, profile cosine similarities. Especially, when analyzing the relationship between authors, we interpreted the research topic by finding the key shared index terms between the authors. In the journal analysis results, 9 journals were largely clustered together in the two clusters of the reformed theology and evangelicalism, but Presbyterian Theological Quarterly that is thought to be a reformed journal was clustered in evangelical cluster. In the index terms analysis results of the clusters, the reformed theology and evangelicalism were key words representing the two clusters. In the authors' analysis results, we had 9 clusters and the Presbyterian theologian studying the reformed theology had the four clusters and the non-Presbyterian theologian had the 5 clusters. Therefore, we consistently had the two clusters of the reformed theology and evangelicalism in all the analysis of the journals and the index terms, the authors.