• Journal of the Korean Chemical Society
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• v.58 no.1
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• pp.118-125
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• 2014

This study purposes to historical approach the formation process of Nature-Study, and to re-evaluate its definition and direction at present. The idea of Nature-Study originated from Campanella, Ratke and Comenius, who emphasized real things. The idea developed through Object Lessons of Sheldon, the Natural History of Agassiz, and Progressivism of Parker. They acted as the main contributors who evolved the idea of Nature-Study and its core fields that involve: 'studying with real things' in Object Lessons which brought the methodical aspects to the idea, 'studying with nature' from Natural History that enhanced the content characteristics and 'learner-centered education' from Progressivism, which impacted the philosophical aspects. Straight (a fellow student of Agassiz) was a teacher for Sheldon Oswego normal school and Parker's Cook County normal school, who synthesized the fields together and paved the way for the formation of Nature-Study. Jackman of Cook Country normal school established Nature-Study as a school curriculum and Bailey and Comstock of Cornell University formed the American Nature-Study Society and as a result, Nature-Study started to gain popularity. However, many educators increasingly rejected Nature-Study as a unifying topic, and preferred the use of textbooks rather than firsthand experiences. This hindered the nature-study movement and it declined since the 1920s. But today, the Nature-study idea can play a huge role in developing science education, inclusive education centered nature, self-initiated retrieval, sympathy with nature and character building of students.

• Convergence Security Journal
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• v.5 no.4
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• pp.41-48
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• 2005

Objective of this study is to design and implement security system based on intrusion tolerance technology for the improvement of dependability in defense system. In order to do so, I identify and extract core technologies through the research and analysis into characteristics, structures, main functions, and technologies of intrusion tolerance architecture. And I accomplish a design of security system through the redundant system based on these core technologies. To implement and verify intrusion tolerance system, I chose 'wargame system' as a subjected system, and accomplished 'Wargame Intrusion Tolerance System' and verified security required functions through a performance test. By applying showed security system into the development of application software based on intrusion tolerance, systematic and efficient system could be developed. Also applying 'WITDS' can solve the current security problems, and this will be basic model for design of security architecture in the federation system after.

• KIPS Transactions on Software and Data Engineering
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• v.4 no.12
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• pp.543-548
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• 2015

Recently top-k query processing has been extremely important along with the explosion of data produced by a variety of applications. Top-k queries return the best k results ordered by a user-provided monotone scoring function. As cloud computing service has been getting more popular than ever, a hot attention has been paid to cloud-based data outsourcing in which clients' data are stored and managed by the cloud. The cloud-based data outsourcing, though, exposes a critical secuity concern of sensitive data, resulting in the misuse of unauthorized users. Hence it is essential to encrypt sensitive data before outsourcing the data to the cloud. However, there has been little attention to efficient top-k processing on the encrypted cloud data. In this paper we propose a novel top-k processing algorithm that can efficiently process a large amount of encrypted data in the cloud. The main idea of the algorithm is to prune unpromising intermediate results at the early phase without decrypting the encrypted data by leveraging an order-preserving encrypted technique. Experiment results show that the proposed top-k processing algorithm significantly reduces the overhead of client systems from 10X to 10000X.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.5
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• pp.41-49
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• 2010

Being popularized the use of portable entertainment/information devices, the demand on flash memory has been also increased radically. In general, flash memory reveals various error patterns by the devices it is mounted, and thus the memory makers are trying to minimize error ratio in the final process through not only the electric test but also the data integrity test under the same condition as real application devices. This process is called an application-level memory test. Though currently various flash memory testing devices have been used in the production lines, most of the works related to memory test depend on the sensual abilities of human testers. In case of testing the flash memory for MP3 devices, the human testers are checking if the memory has some errors by hearing the audio played on the memory testing device. The memory testing process like this has become a bottleneck in the flash memory production line. In this paper, we propose an audio comparison technique to support the efficient flash memory test for MP3 devices. The technique proposed in this paper compares the variance change rate between the source binary file and the decoded analog signal and checks automatically if the memory errors are occurred or not.

• KIPS Transactions on Computer and Communication Systems
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• v.9 no.3
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• pp.45-58
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• 2020

In the current trend of increasing network traffic due to the popularization of cloud service and mobile devices, WAN bandwidth is very low compared to LAN bandwidth. In a WAN environment, a WAN optimizer is needed to overcome performance problems caused by transmission protocol, packet loss, and network bandwidth limitations. In this paper, we analyze the data deduplication algorithm of WANProxy, an open source WAN optimizer, and evaluate its performance in terms of network latency and WAN bandwidth. Also, we evaluate the performance of the two-stage compression method of WANProxy and Zstandard. We propose a new method to improve the performance of WANProxy by revising its data deduplication algorithm and evaluate its performance improvement. We perform experiments using 12 data files of Silesia with a data segment size of 2048 bytes. Experimental results show that the average compression rate by WANProxy is 150.6, and the average network latency reduction rates by WANProxy are 95.2% for a 10 Mbps WAN environment and 60.7% for a 100 Mbps WAN environment, respectively. Compared with WANProxy, the two-stage compression of WANProxy and Zstandard increases the average compression rate by 33%. However, it increases the average network latency by 2.1% for a 10 Mbps WAN environment and 5.27% for a 100 Mbps WAN environment, respectively. Compared with WANProxy, our proposed method increases the average compression rate by 34.8% and reduces the average network latency by 13.8% for a 10 Mbps WAN and 12.9% for a 100 Mbps WAN, respectively. Performance analysis results of WANProxy show that its performance improvement in terms of network latency and WAN bandwidth is excellent in a 10Mbps or less WAN environment while superior in a 100 Mbps WAN environment.

• The KIPS Transactions:PartC
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• v.9C no.1
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• pp.107-114
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• 2002

In these days, rapid advances of the computer system and the high speed network have made the multimedia services popularized among various applications and services in the internet. Internet live broadcasting, a part of multimedia services, makes it possible to provide not only existing broadcasting services including audio and video but also interactive communications which also expand application scopes by freeing from both temporal and spatial limitation. In the Paper, an interned Personal-live broadcasting server system is developed by allowing individual users to actively create or join live-broadcasting services with such basic multimedia devices as a PC camera and a sound card. As the number of broadcasters and participants increases, concurrent multiple channels are established and groups are to be expanded. The system should also guarantee High Availability (HA) for continuous services even in the presence of partial failure of the cluster. Furthermore, a transmission mode switching is supported to consider network environments in the user system.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.251-257
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• 2008

These days Taekkeon of Shin Han-Seong is newly rased as traditional martial which made up in the academic world. The reason why is that create new shaped Traditional Taekkeon which stipulate good points of systematize Martial Arts to register Song Duck-Ki Taekkyeon eleven figures's a piece of skills to cultural assets. This research show how Shin Han-Seong make up Taekkyeon to register to intangible cultural assets, and found next conclusion and meaning. First, skill organization of Song Duk-Ki Taekkeon that is only one modern Taekkeon's initiator have been transmitted for a piece of skills of playing figure which don't have regular system. But Taekkyeon which have regular system have been developed by Shin Han-Seong, finally Taekkyeon is approved to intangible cultural assets. Second, Shin Han-Seong modernized Taekkyeon by borrowing training system of Judo, Fencing, Hapgido, Taekwondo, Karate. But people criticize that Song Duk-Ki Taekkeon is not initiate with original thing. Third, Shin Han-Seong made the grade classification and practical technique screening, Bon-Dae Buigi Twelve part like Pomse of Taekwondo (there is no for traditional Taekkyeon). And he contributed to popularization and modernized learning system by pursuiting sportization. Through this research geared up Taekkyeon's original shape and generational outline about skill transition or composition. And it gave important data for understand about Taekkyeon controversy which scattered.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.10
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• pp.2105-2112
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• 2009

Recently RFID system has been adopted in various fields rapidly. However, we ought to solve the problem of privacy invasion that can be occurred by obtaining information of RFID Tag without any permission for popularization of RFID system To solve the problems, it is Ohkubo et al.'s Hash-Chain Scheme which is the safest method. However, this method has a problem that requesting lots of computing process because of increasing numbers of Tag. Therefore, We suggest the way (process) satisfied with all necessary security of Privacy Protection Shreme and decreased in Tag Identification Time in this paper. First, We'll suggest the SP-Division Algorithm seperating SPs using the Performance Measurement consequence of each node after framing the program to create Hash-Chain Calculated table to get optimized performance because of character of the grid environment comprised of heterogeneous system. If we compare consequence fixed the number of nodes to 4 with a single node, equal partition, and SP partition, when the total number of SPs is 1000, 40%, 49%, when the total number of SPs is 2000, 42%, 51%, when the total number of SPs is 3000, 39%, 49%, and when the total number of SPs is 4000, 46%, 56% is improved.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.12
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• pp.533-540
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• 2013

Anonymity is the one of main reasons for substantial improvement of Internet. It encourages various users to express their opinion freely and helps Internet based distributed systems vitalize. But, anonymity can cause unexpected threats because personal information of an online user is hidden. Especially, distributed systems are threatened by Sybil attack, where one malicious user creates and manages multiple fake online identities. To prevent Sybil attack, the traditional solutions include increasing the complexity of identity generation and mapping online identities to real-world identities. But, even though the high complexity of identity generation increases the generation cost of Sybil identities, eventually they are generated and there is no further way to suppress their activity. Also, the mapping between online identities and real identities may cause high possibility of losing anonymity. Recently, some methods using online social network to prevent Sybil attack are researched. In this paper, a new method is proposed for extracting a user's system-wide Sybil-resistant trust value by using the properties embedded in online social network graphs. The proposed method can be categorized into 3 types based on sampling and decision strategies. By using graphs sampled from Facebook, the performance of the 3 types of the proposed method is evaluated. Moreover, the impact of Sybil attack on nodes with different characteristics is evaluated in order to understand the behavior of Sybil attack.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.1
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• pp.55-64
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• 2013

Due to the popularization of digital high-performance capturing equipments and the emergence of powerful image-editing softwares, it is easy for anyone to make a high-quality counterfeit money. However, the probability of detecting a counterfeit money to the general public is extremely low. In this paper, we propose a counterfeit money detection algorithm using a general purpose scanner. This algorithm determines counterfeit money based on the different features in the printing process. After the non-local mean value is used to analyze the noises from each money, we extract statistical features from these noises by calculating a gray level co-occurrence matrix. Then, these features are applied to train and test the support vector machine classifier for identifying either original or counterfeit money. In the experiment, we use total 324 images of original money and counterfeit money. Also, we compare with noise features from previous researches using wiener filter and discrete wavelet transform. The accuracy of the algorithm for identifying counterfeit money was over 94%. Also, the accuracy for identifying the printing source was over 93%. The presented algorithm performs better than previous researches.