• Journal of the Korea Institute of Information and Communication Engineering
• /
• 제7권7호
• /
• pp.1462-1470
• /
• 2003

According to the necessity about information security as well as the advance of IT system and the spread of the Internet, a variety of cryptography algorithms are being developed and put to practical use. In addition the technique about cryptography attack also is advanced, and the algorithms which are strong against its attack are being studied. If the linear transformation matrix in the block cipher algorithm such as Substitution Permutation Networks(SPN) produces the Maximum Distance Separable(MDS) code, it has strong characteristics against the differential attack and linear attack. In this paper, we propose a new algorithm which cm estimate that the linear transformation matrix produces the MDS code. The elements of input code of linear transformation matrix over GF$({2_n})$ can be interpreted as variables. One of variables is transformed as an algebraic formula with the other variables, with applying the formula to the matrix the variables are eliminated one by one. If the number of variables is 1 and the all of coefficient of variable is non zero, then the linear transformation matrix produces the MDS code. The proposed algorithm reduces the calculation time greatly by diminishing the number of multiply and reciprocal operation compared with the conventional algorithm which is designed to know whether the every square submatrix is nonsingular.

• Steel and Composite Structures
• /
• 제38권2호
• /
• pp.121-139
• /
• 2021

Ultra-high strength concrete (UHSC) encased steel columns are receiving growing interest in high-rise buildings owing to their economic and architectural advantages. However, UHSC encased steel columns are not covered by the modern fire safety design code. A total of 14 fire tests are conducted on UHSC (120 MPa) encased steel columns under constant axial loads and exposed to ISO-834 standard fire. The effect of load ratio, slenderness, stirrup spacing, cross-section size and concrete cover to core steel on the fire resistance and failure mode of the specimens are investigated. The applicability of the tabulated method in EC4 (EN 1994-1-2-2005) and regression formula in Chinese code (DBJ/T 15-81-2011) to fire resistance of UHSC encased steel columns are checked. Generally, the test results reveal that the vertical displacement-heating time curves can be divided into two phases, i.e. thermal expansion and shortening to failure. It is found that the fire resistance of column specimens increases with the increase of the cross-section size and concrete cover to core steel, but decreases with the increase of the load ratio and slenderness. The EC4 method overestimates the fire resistance up to 186% (220 min), while the Chinese code underestimates it down to 49%. The Chinese code has a better agreement than EC4 with the test results since the former considers the effect of the load ratio, slenderness, cross section size directly in its empirical formula. To estimate the fire resistance precisely can improve the economy of structural fire design of ultra-high strength concrete encased steel columns.

• Journal of the Korea institute for structural maintenance and inspection
• /
• 제25권5호
• /
• pp.60-67
• /
• 2021

According to the 「Guidelines of Structural Design for Piloti Building」 of the Ministry of Land, Infrastructure and Transport (2018), the natural period of middle and low rise building of upper-walled lower frame type, such as the domestic multiplex house in piloti style, is suggested for safety to apply the existing code formula of the wall structure. However, the current code formula of the wall structure was provided based on actual measurement of high-rise wall-type structures that mainly exhibit bending behavior. So it is considered that it is not suitable for a piloti-type house with four stories or less, where the wall behaves in shear. See also Park et al. (2000) confirmed that the effect of the lower frame part is greater than that of the upper wall part in the natural period of complex structures with 10 or more floors through analytical studies. Therefore, in this study, in order to examine the effect of the lower frame on the natural period of the middle and low-rise piloti structure, the estimation of natural period by the finite element analysis, approximation formula and ccurrent code formula was performed for the target structures with the shear and flexural stiffness of the upper wall and the shear stiffness of the lower frame as variables. As result, it was found that the change in the shear stiffness of the lower frame had a greater effect on the natural period of the whole building than the change in the bending or shear stiffness of the upper wall.

• Journal of Communications and Networks
• /
• 제6권3호
• /
• pp.209-215
• /
• 2004

In this paper, a butterfly Log-MAP decoding algorithm for turbo code is proposed. Different from the conventional turbo decoder, we derived a generalized formula to calculate the log-likelihood ratio (LLR) and drew a modified butterfly states diagram in 8-states systematic turbo coded system. By comparing the complexity of conventional implementations, the proposed algorithm can efficiently reduce both the computations and work units without bit error ratio (BER) performance degradation.

• Proceedings of the Korea Concrete Institute Conference
• /
• 한국콘크리트학회 1994년도 가을 학술발표회 논문집
• /
• pp.356-361
• /
• 1994

From the previous experimental test results, it has shown that shear that shear strength in lightweight concrete beams was about 85% on that in normal concrete beams. It is speculated that shear connectors in composite beams of steel and lightweight concrete associated with the longitudinal shear strength decrease more in strength than those in normal concrete. So this paper, as a study on strength of shear connectors in composite beams of steel and lightweight concrete slabs, has a purpose to compare the strength formula resulted from the push-out test of thirteen solid slab and four deck Plate slab with the established ones, and then to suggest a proper strength formula of the shear connectors. The established strength formula of the shear connectors is prescribed for $P_ps = 0.50A_s . \sqrt{f_C . E_C}$by AISC coed, but from the experimental test results the strength values of the shear connectors in lightweignt concrete slabs shows about 70% on those of the shear connectors in normal concrete slabs by AISC code. Therefore, as a strength formula this paper suggests to multiply the established strength formula by reduction factor$(\varphi=0.7)$.

• Journal of Welding and Joining
• /
• 제28권1호
• /
• pp.92-99
• /
• 2010

For the last couple of decades many studies have been carried out to find out solutions to improve the effectiveness and productivity of the plate forming process. The practical way for the automation of the plate forming process has not been, however, developed yet. Since the characteristics of heating machines may be different form each other, it is necessary to investigate the thermal deformation characteristics of the heating machine to be used in the automation system. And their characteristics may be updated as new information about thermal deformation by heating is accumulated. In this paper, data base system has been constructed based on the results of experiments and numerical analyses, which will be used in deriving the deformation estimation formula. The computer code which can automatically derive the deformation estimation formula has been also developed. This paper also illustrates how the formula is updated as experimental data are added. From the present findings, it can be said that the automatic deriving procedure may be important in the automated plate forming system since the heating line information to be generated must be directly influenced by the deformation estimation formula.

• Proceedings of the IEEK Conference
• /
• 대한전자공학회 2005년도 추계종합학술대회
• /
• pp.69-72
• /
• 2005

In this paper, pseudo noise (PN) code acquisition performance with multiple antennas in a UWB time hopping/code division multiple access system is analyzed. The closed form for the conditional probability is derived, using the Gauss-Hermite quadrature formula, when the signal with Gaussian distribution goes through the lognormal fading channel. The performance comparison of the above mentioned schemes shows that the code acquisition performance with a diversity combining technique, especially when increasing the number of antennas, is more robust than that using no diversity.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 한국전산구조공학회 2006년도 정기 학술대회 논문집
• /
• pp.575-580
• /
• 2006

Air-operated valves are extensively used for process control and system isolation functions in nuclear power plant, where the safety is primary issue. The purpose of this study is to develop structural analysis code of various air-operated valves such as globe valve, gate valve, and butterfly valve. The thrust formula is derived for valve with the expected weak areas. The expected weak areas are referred from EPRI data. The structural stress analysis is carried out by analytical and commercial FEM code, ANSYS 8.0. The numerical results are compared together and verified on program procedures.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 한국소음진동공학회 2014년도 추계학술대회 논문집
• /
• pp.904-910
• /
• 2014

The Helicopter noise analysis code was developed using Farassat's Formular 1A based on Ffowcs-Williams and Hawkings equation and Lowson's Formula which contains single loading noise source concept. HART-II(Higher harmonic control Aeroacoustic Rotor Test), STAR(Smart-Twisting Active Rotor) and Active-tab Rotor were computed and analyzed by using developed noise code. The results of these rotor noise prediction are explained and its applicability would be mentioned in this paper.

• Herbal Formula Science
• /
• 제30권1호
• /
• pp.19-25
• /
• 2022

Objectives : Huangqintang(⿈芩湯) is a famous herbal prescription in the Traditional Korean Medicine (e.g. Shanghanlun) to treat various chronic disease such as neurological disease and digestive system disease. Its components include Scutellariae Radix(⿈芩), Paeonia lactiflora(芍藥), Glycyrrhizae Radix et Rhizoma(⽢草), Zizyphi Fructus(⼤棗). Methods : In this study, we standardize the name, composition and medical uses of Huangqintang by literature studying and paper searching. Based on the comparison between oriental medicine and modern medicine pharmacology, we linked the medical uses of Huangqintang to Korean Standard Classification of Diseases (KCD). Results and Conclusion : The name of the prescription is unified into "Huangqintang", and its composition ratio between Scutellariae Radix, Paeonia lactiflora, Glycyrrhizae Radix et Rhizoma, and Zizyphi Fructus is 3:2:2:3. Huangqintang is used for enteritis diseases due to its antipyretic and antinflammatory effects. Its medical application was relatied with 'A'code, 'C'code, and 'K'code as indicated by KCD. By standardizing the mixed conceptions of Huangqintang, this review will facilitate the coding of Huangqintang prescription. Therefore, it will make Huangqintang prescription more useful in clinics.