• Korean Journal of Materials Research
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• v.10 no.2
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• pp.155-159
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• 2000

Microstructural processes during high cycle fatigue are investigated according to plastic-strain hardening, crack formation, crack propagation and fracture. It is shown that the fatigue test resembles the uniaxial tensile test. The logarithm of the number of cycles to failure is proportional to the elongation in the tensile test. Under high cycle fatigue test, the strain is normally elastic. If the strain is absolutly elastic, fatigue could not result. But this is over simplication. Nearly all metals undergo a minor amount of plastic strain even at low stress. Damage accumulation leadling to crack formation can continue in the persistent slip bands at very low average plastic strain amplitude. In the ten­s sile test the overall specimen follows the failure procedure whilst in the high cycle fatigue test the local persistent slip band follows the failure procedure. However accumulations of strain per unit volume in the deforming region before failure in both cases are equal locally.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.1 no.2
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• pp.91-98
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• 2008

Domestic standard for Korean T-DMB includes MPEG-4 BSAC (Bit Sliced Arithmetic Coding) audio coding that has been established in 2003. This paper presents an implementation and optimization of MPEG-4 BSAC Audio Decoder on ARM926EJ-S processor. Tools and modules of the BSAC audio decoder were implemented with 32-bit fixed point operations. Further optimization was accomplished using ARM926EJ-S Inline Assembly. The optimization was based on the total number of multiplications and MAC (Multiply and Accumulation) operations causing most of core cycles of ARM926EJ-S, and also based on analysis of ARMv5 instructions. The result of optimization was evaluated on the basis of MIPS (Million Instruction per second). Implementation results show that BSAC bitstream at 96kbps can be decoded in real-time at 65MHz CPU clocks.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.2
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• pp.126-131
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• 2010

The purpose of this study is to assess the condition of composites used in aircraft under varying temperature environment with ultrasound guided wave technique. Investigation of crucial influential factor on the composite health monitoring related to aircraft operational environments such as the number of thermal cycles and temperature deviation between ground level and flight altitude has been of a great concern for aircraft safety issue. In this study, ultrasonic guided wave health monitoring scheme is proposed to evaluate composite specimens damaged with the thermal fatigue simulating aircraft operational condition. Guided wave dispersion curves are used to select right modes which show a promising sensitivity to each different thermal fatigue damage level. The present approach can be also implemented as one of on-lines health monitoring tools for aircraft.

• Journal of Electrochemical Science and Technology
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• v.14 no.1
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• pp.85-95
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• 2023

In recent years, solid-state Li metal batteries (SSLBs) have attracted significant attention as the next-generation batteries with high energy and power densities. However, uncontrolled dendrite growth and the resulting pulverization of Li during repeated plating/stripping processes must be addressed for practical applications. Herein, we report a plastic-crystal-based polymer/ceramic composite solid electrolyte (PCCE) to resolve these issues. To fabricate the one-side ceramic-incorporated PCCE (CI-PCCE) film, a mixed precursor solution comprising plastic-crystal-based polymer (succinonitrile, SN) with garnet-structured ceramic (Li₇La₃Zr₂O₁₂, LLZO) particles was infused into a thin cellulose membrane, which was used as a mechanical framework, and subsequently solidified by using UV-irradiation. The CI-PCCE exhibited good flexibility and a high room-temperature ionic conductivity of over 10^-3 S cm^-1. The Li symmetric cell assembled with CI-PCCE provided enhanced durability against Li dendrite penetration through the solid electrolyte (SE) layer than those with LLZO-free PCCEs and exhibited long-term cycling stability (over 200 h) for Li plating/stripping. The enhanced Li⁺ transference number and lower interfacial resistance of CI-PCCE indicate that the ceramic-polymer composite layer in contact with the Li anode enabled the uniform distribution of Li⁺ flux at the interface between the Li metal and CI-PCCE, thereby promoting uniform Li plating/stripping. Consequently, the Li//LiFePO₄ (LFP) full cell constructed with CI-PCCE demonstrated superior rate capability (~120 mAh g^-1 at 2 C) and stable cycle performance (80% after 100 cycles) than those with ceramic-free PCCE.

• Women's Health Nursing
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• v.21 no.3
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• pp.161-170
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• 2015

Purpose: This study aimed to evaluate the impact of a lifestyle modification program on menstrual irregularity among overweight and obese women with polycystic ovarian syndrome. Methods: A quasi experimental research design was used to conduct this study on 82 women with polycystic ovarian syndrome at the Gynecology and Obesity clinics of Mansoura University Hospital, Egypt. Two groups were included; the study group received a lifestyle modification program for 48 weeks, while the control group was not subjected to this program. Data collection was done for the following variables, a structured interview questionnaire was used to assess the women's general characteristics, menstrual patterns, and 24-hour dietary recall and the researcher took anthropometric measurements and assessed hirsutism by the Ferriman-Gallwey scale. Results: After one year of lifestyle modification, the number of menstrual cycles significantly increased from $2.7{\pm}1.6$ to $6.9{\pm}1.5$ (t=12.26, p<.001) in the study group compared to insignificant minor changes among the control group (t=0.69, p=.488). Additionally, 58.5% were menstruating regularly compared to none in the control group (${\chi}^2=33.93$, p<.001). Conclusion: Participating in a lifestyle modification program was effective in reducing menstrual cycle's irregularity among overweight and obese women with PCOS. Thus, it is recommended to motivate the nurses in counseling the PCOS women on lifestyle modifications.

• Journal of the Korean Geographical Society
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• v.32 no.2
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• pp.217-228
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• 1997

A Study on individual Characteristics and Daily Activities of Housewives in the City of Kwangju. This study examines housewives' daily activities, focusing upon individual characteristics. The data used in this study are based on the fuestionaire survey, asking of personal trip for the weekdays and the weekend. Daily activities are classified into 7 categories and individual characteristics are revealed by age, occupation, a degree of education, number of family, and the residential environment. The results of this study are as follows: 1) The relations between daily activities and individual characteristics are influenced by housewife's occupation. Daily activities of housewives who have jobs are different from those who do not have jobs for a weekday as well as for a weekend. 2) Housewives' daily activities show very busy and vigorous on Saturday. 3) Housewives who are employed are willing to make mutipurpose trips on Saturday. 4) For a weekday, housewives' daily activities are inclined to make one cycle trip in a day, and the more trip cycles are, the more multipurpose trips are made. 5) The relationships between daily activities and individual characteristics show the pattern of WH, WLH, LHLH as it can be grouped.

• Journal of IKEEE
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• v.25 no.1
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• pp.174-179
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• 2021

An Edwards curve cryptography (EdCC) core supporting point scalar multiplication (PSM) on Edwards curves of Edwards25519 and Edwards448 was designed. For area-efficient implementation, finite field multiplier based on word-based Montgomery multiplication algorithm was designed, and the extended twisted Edwards coordinates system was adopted to implement point operations without division operation. As a result of synthesizing the EdCC core with 100 MHz clock, it was implemented with 24,073 equivalent gates and 11 kbits RAM, and the maximum operating frequency was estimated to be 285 MHz. The evaluation results show that the EdCC core can compute 299 and 66 PSMs per second on Edwards25519 and Edwards448 curves, respectively. Compared to the ECC core with similar structure, the number of clock cycles required for 256-bit PSM was reduced by about 60%, resulting in 7.3 times improvement in computational performance.

• The Journal of Bigdata
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• v.5 no.2
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• pp.1-15
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• 2020

The duty-free industry before COVID-19 has continuously grown since 2000, along with the increase of demand in tourism industry. To cope with the increased demand, the duty free companies have kept the strategies which focused on the sales volume. Therefore, they have developed the ways to increase the volume and capacity, not the efficient operations. In the most of previous research, however, authors have proposed the better strategies for marketing and supporting policies. It is very hard to find the previous research which dealt with the operations like logistics and inventory management. Therefore, in this study, it has been predicted the future demand of frequently purchased items in airport duty free shops based on the estimated number of departing passengers by the linear regression, which concluded with the appropriate inventory level. In addition, it has been analyzed the expected effects by introducing the inventory management policy considering the cost and efficiency of operations. Based on the results of this study, it may be possible to reduce total cost and improve productivity by predicting the excessive inventory problems at duty-free shops and improving cycles of supplying items.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.11
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• pp.123-130
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• 2004

This paper describes a multiplier architecture optimized for 32 bit RISC processor with 3-stage pipeline. The multiplier of ARM7, the target processor, is variably carried out on the execution stage of pipeline within 7 cycles. The included multiplier employs a modified Booth's algerian to produce 64 bit multiplication and addition product and it has 6 separate instructions. We analyzed several multiplication algorithm such as radix4-32${\times}$8, radix4-32${\times}$16 and radix8-32${\times}$32 to decide which multiplication architecture is most fit for a typical architecture of ARM7. VLSI area, cycle delay time and execution cycle number is the index of an efficient design and the final multiplier was designed on these indexes. To verify the operation of embedded multiplier, it was simulated with various audio algorithms.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.7
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• pp.159-166
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• 2013

This paper proposes an efficient loop accelerator for a motion estimation specific instruction-set processor. ME algorithms in nature contain complex and multiple loop operations. To support efficient hardware (HW) loop operations, this paper introduces four loop instructions and their specific HW architecture. The simulation results show that the proposed loop accelerator can reduce about 29% average instruction cycles for ME early-termination schemes compared with typical implementation having a combination of compare and conditional jump instructions. The proposed loop accelerator of the motion estimation specific instruction-set processor can significantly reduce the number of program memory accesses and greatly save power consumption. Hence, it can be quite suitable for low power and flexible ME implementation.