• Journal of the Korea Convergence Society
• /
• v.6 no.6
• /
• pp.81-86
• /
• 2015

The threats to privacy and security have received increasing attention as ubiquitous healthcare applications over the Internet become more prevalent, mobile and universal. In particular, we address the communication security issues of access sharing of health information resources in the ubiquitous healthcare environment. The proposed scheme resolves the sender and data authentication problem in information systems and group communications. We propose a novel key management scheme for generating and distributing cryptographic keys to constituent users to provide form of data encryption method for certain types of data concerning resource constraints for secure communications in the ubiquitous healthcare domains.

• Journal of Information Processing Systems
• /
• v.14 no.1
• /
• pp.101-128
• /
• 2018

Thanks to its potential in many applications, Blockchain has recently been nominated as one of the technologies exciting intense attention. Blockchain has solved the problem of changing the original low-trust centralized ledger held by a single third-party, to a high-trust decentralized form held by different entities, or in other words, verifying nodes. The key contribution of the work of Blockchain is the consensus algorithm, which decides how agreement is made to append a new block between all nodes in the verifying network. Blockchain algorithms can be categorized into two main groups. The first group is proof-based consensus, which requires the nodes joining the verifying network to show that they are more qualified than the others to do the appending work. The second group is voting-based consensus, which requires nodes in the network to exchange their results of verifying a new block or transaction, before making the final decision. In this paper, we present a review of the Blockchain consensus algorithms that have been researched and that are being applied in some well-known applications at this time.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2018.05a
• /
• pp.157-158
• /
• 2018

IoT 환경에서는 다양한 센서 디바이스들이 각 디바이스들의 역할과 위치에 따라서 그룹 형태를 이루어 통신을 하게 된다. 그룹 형태의 센서 디바이스들이 통신하는 그룹 기반 통신에서는 수집된 정보를 게이트웨이와 같은 상위 디바이스에게 안전하게 전송해야 한다. 이 때 센서 디바이스들은 게이트웨이와의 인증 과정이 필요하며, 인증 후에 세션키를 분배하여 안전한 통신을 수행할 할 수 있다. 하지만, 일반적인 환경에서는 센서 디바이스의 수가 많아질수록 게이트웨이가 인증을 수행하고 키를 분배하기까지는 매우 큰 오버헤드가 발생하게 된다. 따라서 본 논문에서는 IoT 환경에서 그룹 기반 통신에 대한 보안 요구사항을 분석하고, 그룹 환경에서 사용될 수 있는 그룹 인증 기법에 대해 설계한다.

• Journal of People, Plants, and Environment
• /
• v.24 no.6
• /
• pp.619-628
• /
• 2021

Background and objective: Native to the limestone zones of the Korean Peninsula, Zabelia tyaihyonii is a popular plant for landscaping. As it is now classified as a rare species, the conservation of its genetic resources is necessary. Methods: In this study, which aimed to understand the morphological variation of Z. tyaihyonii, 18 characteristics of Z. tyaihyonii from five habitats were examined. Results: Of these 18 characteristics, 16 characteristics showed significant differences among sites, and the coefficient of variation ranged from 5.4% (for corolla lobe number) to 31.3% (for flower number). Notable variations were observed in the size of flower and calyx lobe. When the corolla length and calyx lobe length were used as the classification key of Z. tyaihyonii, the sites were divided into those with small, intermediate, and large values. Hair was observed on the filament of all samples, a finding which conflicts with an earlier report. Rather than classifying Z. tyaihyonii into different species on the basis of corolla length (COL) and calyx lobe length (CALL) values, we recommend modifying the species description to incorporate the variation in these characteristics of interest. Principal component analysis results showed that the first main component was highly correlated with the traits related to the size of the calyx lobe (length: 0.819, width: 0.758), and the second main component was highly correlated with the traits related with the size of the inflorescence (length: 0.790, width: 0.626). Conclusion: Several notable variations were identified among the characteristics related to inflorescence and calyx lobe. There is little genetic exchange among groups, or each group is influenced by micro environmental factors, because sites that are located nearby. In addition, the difference between COL and CALL, which is used as the classification key for Z. tyaihyonii, was divided into small group, large group, and intermediate group, regardless of the sites' geographical distance.

• Journal of Microbiology and Biotechnology
• /
• v.18 no.5
• /
• pp.852-858
• /
• 2008

An extracellular protease (Mc1) was isolated from the nematode-trapping fungus Monacrosporium cystosporium by gel filtration, anion-exchange, and hydrophobic interaction chromatographies. This protease had a molecular mass of approximately 38 kDa and displayed an optimal activity at pH 7-9 and $56^{\circ}C$ (over 30 min). Its proteolytic activity was highly sensitive to the serine protease inhibitor PMSF (phenylmethylsulfonylfluoride, 0.1 mM), indicating that it belonged to the serine-type peptidase group. The Michaelis constant ($K_m$) and $V_max$ for substrate N-Suc-Ala-Ala-Pro-Phe-pNA were $1.67{\times}10^{-4}\;M$ and 0.6071 $OD_{410}$ per 30 s, respectively. This protease could degrade a broad range of substrates including casein, gelatin, BSA (bovine serum albumin), and nematode cuticle. Moreover, the enzyme could immobilize the free-living nematode Panagrellus redivivus and the pine wood nematode Bursaphelenchus xylophilus, suggesting that it might playa role in infection against nematodes. The encoding gene of Mc1 was composed of one intron and two exons, coding for a polypeptide of 405 amino acid residues. The deduced amino acid sequence of Mcl showed 61.4-91.9% identity to serine proteases from other nematode-trapping fungi. Our results identified that Mcl possessed biochemical properties including optimal reaction condition and substrate preference that are different from previously identified serine proteases.

• Korean Journal of Radiology
• /
• v.22 no.5
• /
• pp.770-781
• /
• 2021

Objective: Chemical exchange-dependent saturation transfer (CEST) MRI is sensitive for detecting solid-like proteins and may detect changes in the levels of mobile proteins and peptides in tissues. The objective of this study was to evaluate the characteristics of chemical exchange proton pools using the CEST MRI technique in patients with dementia. Materials and Methods: Our institutional review board approved this cross-sectional prospective study and informed consent was obtained from all participants. This study included 41 subjects (19 with dementia and 22 without dementia). Complete CEST data of the brain were obtained using a three-dimensional gradient and spin-echo sequence to map CEST indices, such as amide, amine, hydroxyl, and magnetization transfer ratio asymmetry (MTR_asym) values, using six-pool Lorentzian fitting. Statistical analyses of CEST indices were performed to evaluate group comparisons, their correlations with gray matter volume (GMV) and Mini-Mental State Examination (MMSE) scores, and receiver operating characteristic (ROC) curves. Results: Amine signals (0.029 for non-dementia, 0.046 for dementia, p = 0.011 at hippocampus) and MTR_asym values at 3 ppm (0.748 for non-dementia, 1.138 for dementia, p = 0.022 at hippocampus), and 3.5 ppm (0.463 for non-dementia, 0.875 for dementia, p = 0.029 at hippocampus) were significantly higher in the dementia group than in the non-dementia group. Most CEST indices were not significantly correlated with GMV; however, except amide, most indices were significantly correlated with the MMSE scores. The classification power of most CEST indices was lower than that of GMV but adding one of the CEST indices in GMV improved the classification between the subject groups. The largest improvement was seen in the MTR_asym values at 2 ppm in the anterior cingulate (area under the ROC curve = 0.981), with a sensitivity of 100 and a specificity of 90.91. Conclusion: CEST MRI potentially allows noninvasive image alterations in the Alzheimer's disease brain without injecting isotopes for monitoring different disease states and may provide a new imaging biomarker in the future.

• Proceedings of the KSR Conference
• /
• 2005.05a
• /
• pp.957-962
• /
• 2005

Since the nation's currency crisis in 1997. Korea reioined the USD 10.000 per capita income group after collapse of per capita income to USD 6.000 due to the minus GDP growth and sharp hike of exchange rate. It has also been expected for Korea to achieve per capita income of USD 20.000. provided that it maintains $10\%$ export increase rate. $5\%$ nominal GDP growth rate. $3\%$ consumer price index. $2\%$ increase in KRW/USD exchange rate. and $1\%$ net population increase rate. Yet. it should be noted that the nation needs to fulfill the necessity of various SOC infrastructure investment in order to achieve this goal. This paper will address the prospects for the future direction of the national SOC policies through the historical examination of the industrialized nations. such as U.S.A.. U.K.. France. and Japan. with regard to the relationships between economic growth and SOC provision. Some efforts will be made to forecast the optimal budget allocation of the national SOC, in particular, between highway and railway sectors.

• ALGAE
• /
• v.38 no.4
• /
• pp.283-294
• /
• 2023

Previous research indicated that free-living sporangial filament keep hollow morph under high-culture density and form bipartite cells under low-culture density, while the following conchospore release was inhibited by high light. Here, we further explored the molecular bases of these affects caused by light and culture density using a transcriptome analysis. Many differentially expressed genes (DEGs) related to carbon dioxide concentration and fixation, photosynthesis, chlorophyll synthesis and nitrogen absorption were upregulated under high-light conditions compared with low-light conditions, indicating the molecular basis of rapid vegetative growth under the former. The stress response- and ion transport-related DEGs, as well as the gene encoding the vacuole formation-brefeldin A-inhibited guanine nucleotide exchange protein (BIG, py05721), were highly expressed under high-density conditions, indicating the molecular basis of the hollow morph of free-living sporangial filaments under high-culture density conditions. Additionally, the brefeldin A treatment indicated that the hollow morph was directly influenced by vacuole formation-related vesicle traffic. Others DEGs related to cell wall components, zinc-finger proteins, ASPO1527, cell cycle and cytoskeleton were highly expressed in the low density with low-light group, which might be related to the formation and release of conchospores. These results provide a deeper understanding of sporangial filaments in Neopyropia yezoensis and related species.

• Journal of KIISE:Information Networking
• /
• v.30 no.2
• /
• pp.222-232
• /
• 2003

In accordance with the changes in the wireless communication environment, there has been a great need to satisfy the demand for diverse modes of information exchange. Various types of short-distance wireless communication technology have been developed and studied to meet this demand. Among them, Bluetooth which has recently been acclaimed as the standard for short-distance wireless communication, has been the focus of many such studies. However, Bluetooth has weaknesses in its suuity features when its in security services are applied to Home networks. The purpose of this study is to propose a safe Bluetooth scenario with an upgraded suity feature. This paper first reviews the general characteristics and security features of Bluetooth together with an analysis of its weaknesses, and presents the formation and maintenance process of Bluetooth piconet what is created by using ECDSA and group key in the ACL(Asynchronous Connection-less Link) connection through a safe Bluetooth inquiry process.

• Journal of Electrochemical Science and Technology
• /
• v.8 no.3
• /
• pp.183-196
• /
• 2017

The research efforts directed at advancing water electrolysis technology continue to intensify together with the increasing interest in hydrogen as an alternative source of energy to fossil fuels. Among the various water electrolysis systems reported to date, systems employing a solid polymer electrolyte membrane are known to display both improved safety and efficiency as a result of enhanced separation of products: hydrogen and oxygen. Conducting water electrolysis in an alkaline medium lowers the system cost by allowing non-platinum group metals to be used as catalysts for the complex multi-electron transfer reactions involved in water electrolysis, namely the hydrogen and oxygen evolution reactions (HER and OER, respectively). We briefly review the anion exchange membranes (AEMs) and electrocatalysts developed and applied thus far in alkaline AEM water electrolysis (AEMWE) devices. Testing the developed components in AEMWE cells is a key step in maximizing the device performance since cell performance depends strongly on the structure of the electrodes containing the HER and OER catalysts and the polymer membrane under specific cell operating conditions. In this review, we discuss the properties of reported AEMs that have been used to fabricate membrane-electrode assemblies for AEMWE cells, including membranes based on polysulfone, poly(2,6-dimethyl-p-phylene) oxide, polybenzimidazole, and inorganic composite materials. The activities and stabilities of tertiary metal oxides, metal carbon composites, and ultra-low Pt-loading electrodes toward OER and HER in AEMWE cells are also described.