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A Derivation of Potential Korean Exports to Africa
김흥종,Youngho Park 대외경제정책연구원 2002 East Asian Economic Review Vol.6 No.2
The aim of the paper is to derive potential Korean exports to major African countries. Park (2001) adopted conventional RCA and MCA techniques to evaluate the relative performance of Korean exports to draw up a list of recommendable exports to Africa. We improve Park's results in two ways; first, we develop a new indicator reflecting the characteristics of the African market, which was ignored in the former analysis, and second, we derive the RCA and MCA values of Chinese and Japanese exports to Africa and compare them with those of Korean products. The final list of Korea's potential exports to the African market is carefully derived and we find that competing with Japanese exports rather than Chinese ones is a more appropriate strategy for amending Korea's record of underperforming exports to Africa.
Kwon, Soon Jik,Kim, Tae Geun,Park, Youngjun,Kwon, Ohseok,Cho, Youngho The Ecological Society of Korea 2015 Journal of Ecology and Environment Vol.38 No.4
This study was performed to provide important basic data for the preservation and management of Scopura laminata, a species endemic to Korea, by elucidating the spatial characteristics of its present, potential, and future distribution areas. Currently, this species is found in the Odaesan National Park area of South Korea and has been known to be restricted in its habitat due to its poor mobility, as even fully grown insects do not have wings. Utilizing the MaxEnt model, 20 collection points around Odaesan National Park were assessed to analyze and predict spatial distribution characteristics. The precision of the MaxEnt model was excellent, with an AUC value of 0.833. Variables affecting the potential distribution area of S. laminata by more than 10% included the range of annual temperature, seasonality of precipitation, and precipitation of the driest quarter, in order of greatest to least impact. Compared to the current potential distribution area, no significant difference in the overall habitable area was predicted for the 2050s or 2070s. It was, however, demonstrated that the potential habitable area would be reduced in the 2050s by up to 270.3 km from the current area of 403.9 km; further, no potential habitable area was anticipated by the 2070s according to our predictive model. Taken together, it is anticipated that this endemic species could be significantly affected by climate changes, and hence effective countermeasures are strongly warranted for the preservation of habitats and species management.
A Secure Incentive Scheme for Vehicular Delay Tolerant Networks Using Cryptocurrency
Park, Youngho,Sur, Chul,Rhee, Kyung-Hyune Hindawi Limited 2018 Security and communication networks Vol.2018 No.-
<P>One remarkable feature of vehicular ad hoc networks is characterized by an opportunistic communications by means of store-carry-forward message relaying which requires the cooperation of vehicles on the networks. However, we cannot be sure that all vehicles willingly contribute their computing resources to the networks for message forwarding with no rewards for their efforts in real-world scenarios. In addition, unfortunately, there may exist some selfish and greedy node which may not help others but tend to take their own gain. To cope with this challenge, incentive mechanisms are generally considered as the promising solution. In this paper, we design a Bitcoin-based secure and reliable incentive scheme for cooperative vehicular delay tolerant networking services. Bitcoin is the well-known worldwide cryptocurrency and digital payment system whose implementation relies on cryptographic techniques, which makes it possible to develop a practical credit-based incentive scheme on the vehicular networks at a low cost. We also implement Bitcoin transaction scripts to handle our proposed incentive scheme.</P>
Youngho Cho,Jeong Sun Park,Min Jee Kim,Deuk-Soo Choi,Sang-Ho Nam,Iksoo Kim 한국응용곤충학회 2013 한국응용곤충학회 학술대회논문집 Vol.2013 No.04
Hipparchia autonoe belongs to the family Nymphalidae (Lepidoptera) and is designated as an endangered insect and national monument in Korea. It only inhabits a very restricted area on Mt. Halla but is widely distributed in several Asian countries including Mongolia. A previous study conducted to understand the genetic relationship between Mt. Halla and Mongolian H. autonoe for conservation purposes suffered from a limited number of samples. Therefore, we sequenced the DNA barcode region of an additional 36 H. autonoe individuals, combined them with previous data from 19 individuals, and performed phylogenetic and population genetic analyses. Furthermore, the internal transcribed spacer 2 (ITS2) region was also sequenced from the 36 samples as a nuclear DNA marker. The existence of independent haplotypes, sequence types, and significant FST estimates (p < 0.05) between Mt. Halla and Mongolian populations indicated hampered gene flow between the populations. Nevertheless, an absence of a reciprocal monophyletic group in Mt. Halla and Mongolian populations by cytochrome oxidase subunit I gene- and ITS2-based phylogeny suggests that the genetic isolation of the Mt. Halla population from the Mongolian populations seemed not large enough to consider them independent genetic entities.
Secure Private Key Revocation Scheme in Anonymous Cluster -Based MANETs
Park, YoHan,Park, YoungHo Korea Multimedia Society 2015 멀티미디어학회논문지 Vol.18 No.4
Security supports are a significant factor in the design of mobile ad hoc networks. In the dynamic topology where the node changes frequently, private key generation and revocation for newly joining and leaving nodes must be considered. In addition, the identities of individual nodes must be protected as well in mobile networks to avoid personal privacy concerns. This paper proposes ID-based private key revocation scheme and non-interactive key agreement scheme in anonymous MANETs. The proposed scheme provides the user privacy using pseudonyms and private key generation and revocation schemes with consideration of dynamic user changes. Therefore, our schemes can be applied in dynamic and privacy-preserving MANETs which are helpful to share multimedia data.
Enhanced nonlinear optical characteristics of copper-ion-doped double crossover DNAs.
Park, Byeongho,Lee, Byung Jic,Dugasani, Sreekantha Reddy,Cho, Youngho,Kim, Chulki,Seo, Minah,Lee, Taikjin,Jhon, Young Min,Choi, Jaebin,Lee, Seok,Park, Sung Ha,Jun, Seong Chan,Yeom, Dong-Il,Rotermund, RSC Pub 2015 Nanoscale Vol.7 No.43
<P>The modification of deoxyribonucleic acid (DNA) samples by sequencing the order of bases and doping copper ions opens the possibility for the design of novel nanomaterials exhibiting large optical nonlinearity. We investigated the nonlinear characteristics of copper-ion doped double crossover DNA samples for the first time to the best of our knowledge by using Z-scan and four-wave mixing methods. To accelerate the nonlinear characteristics, we prepared two types of unique DNA nanostructures composed of 148 base pairs doped with copper ions with a facile annealing method. The outstanding third-order nonlinear optical susceptibility of the copper-ion-doped DNA solution, 1.19 ?? 10(-12) esu, was estimated by the conventional Z-scan measurement, whereas the four-wave mixing experiment was also investigated. In the visible spectral range, the copper-ion-doped DNA solution samples provided competent four-wave mixing signals with a remarkable conversion efficiency of -4.15 dB for the converted signal at 627 nm. The interactions between DNA and copper ions contribute to the enhancement of nonlinearity due to structural and functional changes. The present study signifies that the copper-ion-doped double crossover DNA is a potential candidate as a highly efficient novel material for further nonlinear optical applications.</P>