• Journal of the Korean Professional Engineers Association
• /
• v.15 no.4
• /
• pp.12-24
• /
• 1982

East Parts of Bangladesh have been benifited by low cost energy generated by domestic natural gas but West parts where energy generated by imported fuel. Bangladesh Government authority has very much concerned to transmit the low cost electricity to the West from the East for past several years. To solve such concerns, cross-country 230kv double circuits Power transmission line was proposed, however there was a big obstacle for the realization of this line to cross the Jamuna river which has 12 km long width with a deep muddy river bed. A consultant engineering firm named Merz-Mclellan anyway finalized this plan and a world-wide bid was announced on June 31, 1979. Due to the expected difficulty to construct the towers on sea like area, only three construction groups have participated. including a Korean joint venture organization of Samsung-Korean Developement corporation-Kolon Electric Machinery company. After 3 months bid evaluation, contract was awarded to Korean Consosium and KEM Co was in charge of designing steel towers with anchor bolts and base plates beside to electrical engineering field. Then KEM Co have faced and over-comed many unenpected technical difficulties such as forced eccentricity joint on base plate, distorsion issue of 60mm thick plates welding, threading anchor bolts, tad heat treatment of some anchor bolts, disagreement from Consultant Engineer on multiplying factor of leg stresses for 45$^{\circ}$ wind and on reducing O.L.F for wind loads on cables for such 1220km long spans. After spending two years long period for designing and engineering towers, base plates, and anchor bolts, first shipment of tower was finally realized on Nov. 8, 1981 and on the other hand KDD has proceeded concrete caisson work on schedule at Jamuna river site and expected to complete tower erection and stringing of cables within this year of 1982 which was original completion target.

• 한국정보교육학회:학술대회논문집
• /
• 2011.01a
• /
• pp.211-217
• /
• 2011

Recent IT (information technology) environmental changes, such as emerging social network services or increasing user participation in multimedia environment, have made it necessary for e-learning systems to undergo changes in various ways. Metadata is an agreement for interoperability between different systems. The standardization of metadata for e-learning system has been driven by some domestic and international organizations, but applying diverse environmental changes into the design of e-learning metadata is in dire need. In this paper, we present a methodology for the analysis and design of modeling e-learning metadata and elicit the design requirements, on the basis of the metadata standard KEM 3.0, about the elements that are expected to be needed in future e-learning systems. Based on the requirements from the analysis, we present the three-layer model for classifying the requirements by the importance of metadata elements per Kana Model. An intelligent e-learning system is to be developed based on the proposed modeling design, which we hope to influence the development of an international standard in the future.

• The Journal of Korean Association of Computer Education
• /
• v.7 no.2
• /
• pp.25-34
• /
• 2004

Sixteen provincial Research Institute of Education and Science(RISE) in the country have provided good qualified multimedia educational materials that was produced by some special skilled teachers to elementary, middle and high school teachers using web services. And moreover KERIS and KICE have also produced educational materials and have a plan to integrate distributed multimedia educational materials that RISE produced. The development of KERIS's KEM metadata in 2001 and the making of educational material metadata of RISE is the first step of integration plan. These metadata can be used to make integration plan possible. But before taking integration plan, the study of how to integrate and manage it should be performed. Therefore, this paper introduces the technique of XML web service and JDBC with 3-tier system as the method of integrate distributed educational material metadata. The evaluation shows these two methods have similar response time with MS SQL Server 2000 and Oracle 9i. Thus, we conclude that JDBC and XML web service can be the proper solution to search XML-formatted metadata.

• The Journal of Korean Association of Computer Education
• /
• v.9 no.6
• /
• pp.29-39
• /
• 2006

The Web is evolving quantitatively into an explosive development. However, users usually have heavy burden of searching information because of the absence of contextual meaning on the Web. Due to an enormous amount of information, users have to endure for finding strong cohesive keywords by themselves and read each of the documents with enduring effort. This paper proposes an efficient method of searching more relative documents than current KEM-based searching systems on the Web by using contextual meaning. We designed a domain ontology on computer hardware, and a searching system which was searching those e-Learning objects. Owing to the Ontology-applied search system, information such as educational materials and related multimedia can be easily provided to the users. Further, learners could be informed of relationship of knowledge, e.g., class hierarchy, properties and values, and so on. The request results are semantically related to users' needs, and thus the system provides a learner-centered searching.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.30 no.5
• /
• pp.781-793
• /
• 2020

In this paper, we propose a new RLWE-based scheme named μ-Hope that exploits Error Correcting Code(ECC) on NewHope. The previous parameters of NewHope uses 12289 as a prime modulus, and the size of the public key, private key, and ciphertext is 928-byte, 1888-byte, and 1120-byte respectively, which can be said to be larger than other RLWE based algorithms. In this paper, we propose μ-Hope, which changes modulus 12289 to 769 to reduce the size of the public key, private key, and ciphertext. Also, we adopts XE1 as an Error Correcting Code(ECC) to solve the increased decryption failure rate caused by using a small prime modulus. As a result, the size of the public key, private key, and ciphertext decreased by 38%, 37%, and 37% respectively. As the computational efficiency caused by using a small prime modulus exceeds the performance degradation by exploiting ECC, this result in 25% performance improvement for a single key exchange.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.31 no.3
• /
• pp.463-471
• /
• 2021

Since 2016, National Institute of Standards and Technology (NIST) has been conducting a post quantum cryptography standardization project in preparation for a quantum computing environment. Three rounds are currently in progress, and most of the candidates (5/7) are lattice-based. Lattice-based post quantum cryptography is evaluated to be applicable even in an embedded environment where resources are limited by providing efficient operation processing and appropriate key length. Among them, SABER KEM provides the efficient modulus and Toom-Cook to process polynomial multiplication with computation-intensive tasks. In this paper, we present the optimized implementation of evaluation and interpolation in Toom-Cook algorithm of SABER utilizing ARM/NEON in ARMv8-A platform. In the evaluation process, we propose an efficient interleaving method of ARM/NEON, and in the interpolation process, we introduce an optimized implementation methodology applicable in various embedded environments. As a result, the proposed implementation achieved 3.5 times faster performance in the evaluation process and 5 times faster in the interpolation process than the previous reference implementation.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.32 no.6
• /
• pp.1045-1057
• /
• 2022

Recently, the National Institute of Standards and Technology (NIST) announced four cryptographic algorithms as a standard candidates of Post-Quantum Cryptography (PQC). In this paper, we show that private key can be exposed by a non-profiling-based power analysis attack such as Correlation Power Analysis (CPA) and Differential Deep Learning Analysis (DDLA) on CRYSTALS-KYBER algorithm, which is decided as a standard in the PKE/KEM field. As a result of experiments, it was successful in recovering the linear polynomial coefficient of the private key. Furthermore, the private key can be sufficiently recovered with a 13.0 Normalized Maximum Margin (NMM) value when Hamming Weight of intermediate values is used as a label in DDLA. In addition, these non-profiling attacks can be prevented by applying countermeasures that randomly divides the ciphertext during the decryption process and randomizes the starting point of the coefficient-wise multiplication operation.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.33 no.5
• /
• pp.709-719
• /
• 2023

Recently, Post-Quantum Cryptography (PQC), which is secure against attacks using quantum computers, has been actively studied. In 2022, the KpqC competition, a competition for domestic PQC standardization, was launched, and a total of 16 candidate algorithms were received, and the first round is underway. In this paper, we apply Alexander May's Meet-LWE attack to TiGER, a lattice-based key encapsulation mechanism that is a candidate for the first round of the KpqC competition, and analyze its concrete attack complexity. The computational results of applying the Meet-LWE attack to each of the proposed parameters of TiGER show that the proposed TiGER192 parameter, which targets 192-bit quantum security, actually achieves 170-bit classical security. In addition, we propose a parameter setting to increase the attack complexity against the Meet-LWE attack.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.34 no.2
• /
• pp.157-166
• /
• 2024

Probability of decryption failure of a public key cryptography based on LWE(learning with errors) is determined by its architecture and parameter settings. Since large decryption failure probability leads to attacks[1] on scheme as well as degradation of performance, TiGER[2], a Ring-LWE(R)-based KEM proposed for the first round of KpqC, tried to reduce the decryption failure probability by using error correction code Xef and D2 encoding method. However, D'Anvers et al. has shown that the commonly assumed independence of each bit error is not established since in the case of an encryption scheme based on Ring-LWE(R) using an error correction code, there is error dependency which is not negligible[3]. In this paper, since TiGER does not consider the error dependency, we calcualte the decryption failure probability of TiGER by considering the error dependency. In addition, we found that the bit error probability is incorrectly calculated in TiGER, so we present the correct calculation.

• 한국정보교육학회:학술대회논문집
• /
• 2007.08a
• /
• pp.221-226
• /
• 2007

군 복무 중 이러닝을 통해 군 장병의 자기 계발을 돕기 위해 정부는 군 이러닝 포털시스템을 구축하였다. 본 연구에서는 군 이러닝 포털 시스템을 통해 다양한 교육용 콘텐츠를 제공하기 위해 교육용 콘텐츠에 대한 메타데이터를 설계하였다. 군 장병들이 원하는 콘텐츠와 이를 표현하는 방법에 대한 설문 조사를 통해 요구 분석하였으며, 이를 토대로 분류 체계와 분류 항목을 선정하였다. 이러한 분류 체계와 분류 항목을 KEM과 SCORM과 같은 국내 외 콘텐츠 표준화 규격을 참조하여 교육 콘텐츠 메타데이터로 설계하였다.