• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.4
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• pp.381-400
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• 1985

Twelve species of subfamily Leuciscinae from Korea are reviewed and keys to species and genera are provided. The species include Tribolodon hakonensis, T. branti, Phoxinus phoxinus, Moroco oxycephalus, M. steindachneri, M. keumgang, M. semotilus, Zacco platypus, Z. temminckii, Opsariichthys uncirostris amurensis, Aphyocypris chinensis and Squaliobarbus curriculus. In the present study M. lagowskii and O. bidens recorded previously in Korea have to be classified to M. steindachneri and O.u.amurensis based on several characters such as caudal peduncle depth, their distributions and lateral line scales, etc. A. chinensis from Korea is easily distinguished from that of mainland China in head length and caudal peduncle length. The skull and weberian apparatus of M. keumgang, endemir to Korea are described and compared with the other species of this subfamily. The diploid chromosome number of 9 species has three patterns: 2n=50 (T. hakonensis, P. phoxinus, M. oxycephalus, M. steindachneri and M. keumgang), 2n=48(Z. platypus, Z. temminckii and A. chinensis), 2n=76 (O. u. amurensis). Polyploidization or intraspecific polymorphism of chromosome was not observed in any species studied. Both species of P. phoxinus and A. chinensis are shown to be electrophoretically distinct from other taxa examined. The genera of subfamily Leuciscinae in Korea are represented by three possible groups: 1) Zacco-Opsariichthys-Tribolodon-Phoxinus-Morco, 2) Aphyocypris, and 3) Squaliobarbus.

• Parasites, Hosts and Diseases
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• v.50 no.3
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• pp.207-213
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• 2012

The egg morphology of minute intestinal flukes (MIF) that can occur as human infections in the Republic of Korea, i.e., Metagonimus yokogawai, M. miyatai, M. takahashii, Heterophyes nocens, Heterophyopsis continua, Stellantchasmus falcatus, Stictodora fuscata, Pygidiopsis summa, and Gymnophalloides seoi, was studied in comparison with Clonorchis sinensis. The adult worms were obtained from residents of endemic areas, and their intrauterine eggs were studied and measured using light microscopy; the length, width, length-width ratio (LWR), and Faust-Meleney index (FMI). Several specimens were processed for scanning electron microscopy (SEM), and before gold-coating, the uterine portion of each fluke was etched with a sharp pin in order to expose the eggs. The MIF eggs were ovoid, pyriform, or elliptical with a size range of $21-35{\times}12-21{\mu}m$. S. fuscata eggs revealed the highest FMI (largest in the area) and lowest LWR, whereas P. summa eggs showed the lowest FMI and medium LWR. SEM revealed that G. seoi and S. fuscata had remarkably clean shell surface lacking the muskmelon-like structure which is prominent in C. sinensis eggs. In Metagonimus spp., H. continua, H. nocens, and S. falcatus eggs, minute surface ridges were recognizable though less prominent compared with C. sinensis. On the surface of P. summa eggs, thread-like curly structures were characteristically seen. The results revealed that important differential keys for MIF eggs include the length, width, area (FMI), shape of the eggs, and the extent of the muskmelon-like structure or ridges on their shell surface and operculum.

• Review of Korean Society for Internet Information
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• v.14 no.3
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• pp.78-85
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• 2013

The revelations made possible by Edward Snowden, a contractor of the US intelligence service NSA, are a sobering reminder that the Internet is not an 'anonymous' means of communication. In fact, the Internet has never been conceived with anonymity in mind. If anything, the Internet and networking technologies provide far more detailed and traceable information about where, when, with whom we communicate. The content of the communication can also be made available to third parties who obtain encryption keys or have the means of exploiting vulnerabilities (either by design or by oversight) of encryption software. Irrebuttable evidence has emerged that the US and the UK intelligence services have had an indiscriminate access to the meta-data of communications and, in some cases, the content of the communications in the name of security and protection of the public. The conventional means of judicial scrutiny of such an access turned out to be ineffectual. The most alarming attitude of the public and some politicians is "If you have nothing to hide, you need not be concerned." Where individuals have nothing to hide, intelligence services have no business in the first place to have a peek. If the public espouses the groundless assumption that State organs are benevolent "( they will have a look only to find out whether there are probable grounds to form a reasonable suspicion"), then the achievements of several hundred years of struggle to have the constitutional guarantees against invasion into privacy and liberty will quickly evaporate. This is an opportune moment to review some of the basic points about the protection of privacy and freedom of individuals. First, if one should hold a view that security can override liberty, one is most likely to lose both liberty and security. Civilized societies have developed the rule of law as the least damaging and most practicable arrangement to strike a balance between security and liberty. Whether we wish to give up the rule of law in the name of security requires a thorough scrutiny and an informed decision of the body politic. It is not a decision which can secretly be made in a closed chamber. Second, protection of privacy has always depended on human being's compliance with the rules rather than technical guarantees or robustness of technical means. It is easy to tear apart an envelope and have a look inside. It was, and still is, the normative prohibition (and our compliance) which provided us with protection of privacy. The same applies to electronic communications. With sufficient resources, surreptitiously undermining technical means of protecting privacy (such as encryption) is certainly 'possible'. But that does not mean that it is permissible. Third, although the Internet is clearly not an 'anonymous' means of communication, many users have a 'false sense of anonymity' which make them more vulnerable to prying eyes. More effort should be made to educate the general public about the technical nature of the Internet and encourage them to adopt user behaviour which is mindful of the possibilities of unwanted surveillance. Fourth, the US and the UK intelligence services have demonstrated that an international cooperation is possible and worked well in running the mechanism of massive surveillance and infiltration into data which travels globally. If that is possible, it should equally be possible to put in place a global mechanism of judicial scrutiny over a global attempt at surveillance.

• Korean Journal of Ecology and Environment
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• v.51 no.1
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• pp.40-59
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• 2018

This review summarizes the history of freshwater zooplankton research in Korean Society of Limnology and necessary future topics that are remain poorly investigated in South Korea based on main research topics of published articles focusing on lakes, reservoirs, rivers and wetland ecosystems. In Korea, a total 450 freshwater zooplankton species have been reported (85 species of cladocera, ca. 230 species of rotifera since 1939, and 138 species of copepoda), and they cover 10% of total zooplankton species list. In the present paper, we provide recent species list of zooplankton found in Korea and their taxonomic keys. Over periods of 45 years, there are 25 published papers for zooplankton biota in lentic ecosystems in Korean Journal of Ecology and Environment (KJEE). The ecology of zooplankton communities in rivers has focused on the mechanisms involved in regulating their abundance, diversity and spatio-temporal patterns of genus Bosmina and rotifers (genus Brachionus and Keratella) that are most frequently found from Korea. On the other hand, the studies on zooplankton in wetland has focused on Alona, Chydorus and Ceriodaphnia with special emphasis on their relationships with aquatic macrophytes. Even though studies on the freshwater ecosystem in Korea have a long history, a few of studies on zooplankton biota were conducted at rice paddy, Dumbeong and wetlands. During the last two decades, experimental advances in freshwater zooplankton ecology and understanding of structure and function of this biota were made from a series of articles mainly in journal of KJEE. For future studies, quantitative, experimental and interdisciplinary approaches would be key words to understand zooplankton ecology and their roles in aquatic ecosystems under changing environments, and we have suggested necessary zooplankton research fields and future directions.

• Applied Microscopy
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• v.36 no.3
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• pp.195-208
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• 2006

Using light and scanning electron microscopy morphological studies of pollens were conducted to determine the sectional boundary and the relationships among eight species of section Zygophyllidium and its five related species of subg. Poinsettia. Pollen characters of 13 species were described, and their diagnostic keys were presented here. Based on the sculpturing patterns and the results of numerical analysis using 10 pollen characters 13 species were divided into four Pollen types: type I, having micro-reticulate shaped pollen (E. hexagona, E. lagunensis, E. hexagonoides and E. bilobata), type II, having reticulate shaped pollen (E. delicatula, E. extipulata, E. dentata, E. heterophylla, E. pulcherrima and E. cyathophora), type III, micro-reticulate shaped pollen with platten muri (E. lacera), and type IV, haying foveolate shaped pollen grains (E. chersonesa and E. eriantha). The results of pollen morphological studies suggest that the sect. Zygophyllidium should be delimited based on only four species, E. hexagona, E. lagunensis, E. hexagonoides and E. bilobata, E. delicatural and E. exstipulata of sect. Zygophyllidium must be transferred to subg. Poinsettia based on pollen morphology. E. eriantha and E. chersonesa having forveolate sculpturing pattern of pollen grains seem to be closely related with species from subg. Agaloma, and additional studies of these species are needed to determine the species relationships within Agaloma group.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.1
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• pp.33-46
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• 2003

A Home Location Register(HLR) database system manages each subscriber's location information, which continuously changes in a cellular network. For this purpose, the HLR database system provides table management, index management, and backup management facilities. In this thesis, we propose using a two-level index method for the mobile directory number(MDN) as a suitable method and a chained bucket hashing method for the electronic serial number(ESN). Both the MDN and the ESN are used as keys in the HLR database system. We also propose an efficient backup method that takes into account the characteristics of HLR database transactions. The retrieval speed and the memory usage of the two-level index method are better than those of the R-tree index method. The insertion and deletion overhead of the chained bucket hashing method is less than that of the modified linear hashing method. In the proposed backup method, we use two kinds of dirty flags in order to solve the performance degradation problem caused by frequent registration-location operations. For a million subscribers, proposed techniques support reduction of memory size(more than 62%), directory operations (2500,000 times), and backup operations(more than 80%) compared with current techniques.

• Journal of Broadcast Engineering
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• v.18 no.5
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• pp.758-770
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• 2013

In a Broadcast Encryption System, a sender sends an encrypted message to a large set of receivers at once over an insecure channel and it enables only users in a target set to decrypt the message with their private keys. In 2005, Boneh et al. proposed a fully collusion-resistant public key broadcast encryption in which the ciphertext and the privatekey sizes are constant. In general, pairing-based broadcast encryption system is efficient in bandwidth and storing aspects than non-pairing based broadcast encryption system, however, it requires many computational costs that resource-constrained devices is not suit to be applied. In this paper, we propose a Broadcast Encryption scheme(called BEWD) that user can decrypt a ciphertext more efficiently. The scheme is based on Boneh et al.scheme. More precisely, it reduces receiver's computational costs by delegating pairing computation to a proxy server which computation is required to receiver in Boneh et al.scheme. Furthermore, the scheme enables a user to check if the proxy server compute correctly. We show that our scheme is secure against selective IND-RCCA adversaries under l-BDHE assumption.

• Journal of the Korea Society of Computer and Information
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• v.20 no.6
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• pp.1-11
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• 2015

Recently, NAND flash memories are used for storage devices because of fast access speed and low-power. However, applications of FTL on low power computing devices lead to heavy workloads which result in a memory requirement and an implementation overhead. Consequently, studies of B+-Tree on embedded devices without the FTL have been proposed. The studies of B+-Tree are optimized for performance of inserting and updating records, considering to disadvantages of the NAND flash memory that it can not support in-place update. However, if a general garbage collection method is applied to the previous studies of B+-Tree, a performance of the B+-Tree is reduced, because it generates a rearrangement of the B+-Tree by changing of page positions on the NAND flash memory. Therefor, we propose a novel garbage collection method which can apply to the B+-Tree based on the NAND flash memory without the FTL. The proposed garbage collection method does not generate a rearrangement of the B+-Tree by using a block information table and a proxy block. We implemented the B+-Tree and ${\mu}$-Tree with the proposed garbage collection on physical devices with the NAND flash memory. In experiment results, the proposed garbage collection scheme compared to greedy algorithm garbage collection scheme increased the number of inserted keys by up to about 73% on B+-Tree and decreased elapsed time of garbage collection by up to about 39% on ${\mu}$-Tree.

• Korean Journal of Plant Taxonomy
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• v.45 no.4
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• pp.332-352
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• 2015

The tribe Neillieae, a small group of about 18 species in the Rosaceae, comprises three taxonomically difficult genera, Neillia, Physocarpus, and Stephanandra. The tribe, characterized by lobed leaves with persistent or deciduous stipules and ovoid, shiny seeds with copious endosperm, is strongly supported as a monophyletic group by a variety of lines of molecular evidence. Due to the high amount of morphological variation across the three genera and the species in tribe Neillieae, conflicting classification schemes and numerous species have been proposed over the past three centuries. However, no comprehensive systematic study of the group, including all species across their geographic ranges, has ever been undertaken. As part of a taxonomic revision of tribe Neillieae, a revision of Physocarpus based on the morphological examination of herbarium specimens, including types, and field observation is presented. Artificial keys, comprehensive nomenclatural treatments, descriptions, distribution maps, and lists of specimens examined are provided. Six species in Physocarpus are recognized. A lectotype is here designated for the following species: Opulaster pubescens, Opulaster ramaleyi, Spiraea opulifolia var. parvifolia, Spiraea opulifolia var. tomentella, Physocarpus michiganensis, and Physocarpus missouriensis.

• 보존과학연구
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• s.27
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• pp.5-22
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• 2006

Mireuksa is a temple that was established in the Baekjea Period and continued around to the 16thcentury. The sites of the temple throughout diverse periods such as the United Shilla Period, KoryuPeriod, and Chosun Period including the one of the early temple in the late Baekjea Period were discovered. In those temple sites, there were lots of diverse artifacts discovered including artifacts in the Bronze Age. In this study, the compositions of four bronze bells excavated from Mireuksa site in Iksan were analyzed and the manufacturing technique of bronze bells was studied through the observation of microstructure. Also, the analytical cases of ancient bronze bells were collected and compared. Furthermore, the provenance study of the bronze bells site was attempted with the Pbisotope ratio. The results aim to offer crucial keys for discovering the aspect of society as well as information about the origin, development, and the route of propagation of ancient technologies. Bronze bell No. 1 showed an unexpected composition as Cu was found 98.5% in it. There were shown twins which were created by annealing and an even phase in the fine grains. It was also shown that bronze bell No. 2 and 4 had a high content of Pb although they showed a similar composition with general bronze bells in terms of Sn content. As shown in the analysis characteristics table of Korean bronze bell of this study, the ancient bronze bell used Pb of which content was limited to 2.12% in general, however, the results showed 15.5% and 13.2% respectively, which is an excessive amount. Asa result of analyzing inclusion in the microstructure of bronze bell No. 2, it was found that sulfide group mineral was used since there appeared S(14.55%). Also, it was proven that $CuFeS_2$ or$Cu_5FeS_4$ was used as a raw material because there was a small amount of Fe. As a result of analyzing inclusion of bronze bell No. 4, the bronze bell sample contained S(13.43%) and it is thought that sulfide group mineral was used, however, it had no Fe. Therefore, it is not connected to $CuFeS_2$ which is the main mineral of Korea. In addition, a strain line was shown with processing in bronze bell No. 2 and 4. As a result of provenance study of bronze bell No. 2 and 4 using the Pb isotope ratio, they or their raw materials are estimated to come from the southern China. Bronze bell No. 3 showed only Cu and Sn, and it is featured with a relatively low amount of Sn(6.63%). The microstructure has only phase, andintergranular corrosion was highly in progress.