• 대한기계학회논문집A
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• 제37권6호
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• pp.731-738
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• 2013

본 논문은 6 륜 독립구동/독립조향 차량의 독립 스티어-바이-와이어 장치의 고장 안전 주행 제어방법을 제시하였다. 조향부 고장 휠의 횡방향 타이어 힘이 차량 선회 운동에 저항력으로 작용할 수 있으므로, 이를 줄이기 위하여 본 고장 안전 주행 제어 알고리즘은 조향부 고장 휠에 높은 슬립률이 발생하도록 토크 입력을 가한다. 고슬립으로 인한 조향부 고장 휠의 종방향 타이어 힘 증가를 고려하기 위하여 종방향 타이어 힘을 추정하여 고장나지 않은 휠의 구동력 최적 분배에 구속 조건에 포함시킨다. 개루프 조향 및 폐루프 조향 시뮬레이션 결과 조향부 고장이 발생한 차량의 주행시 고장을 고려하지 않은 최적 구동력 분배 제어에 비하여 본 알고리즘 적용시 차량의 주행 성능이 보정됨을 확인하였다.

• 한국산학기술학회논문지
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• 제12권12호
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• pp.5518-5524
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• 2011

사람이 서있는 동안의 안정성 감소는 낙상에 영향을 끼치는 요인 중 하나이다. 따라서 본 논문은 낙상 발생률이 높은 65세 이상의 노인여성을 대상으로 균형기능 검사를 실시하고, 성인여성의 연령대별 비교를 통해 균형능력이 노화에 따라 변화해가는 정형외과 및 신경학적 요인들을 밝혀 낙상을 예방하고자 한다. 연구 대상자는 보조기나 약물복용 없이 독립보행이 가능한 65세 이상의 신체 건강한 노인여성 10명(평균연령: 71.9세)과 성인여성 10명(평균연령: 23.2세)으로 하였다. 균형능력 평가장치(Tetrax)를 이용하여 8가지 자세에 대한 안정성 지수(Stability Index, ST), 푸리에 지수(Fourier index, F), 체중분표(Weight Distribution (%), WD), 체중분포율 지수(Weight Distribution Index, WDI), 동기화 지수(Synchronization Index, SI), 낙상율지수(fall index, FI)를 측정하였다. 그 결과, 안정성 지수(ST)는 노인여성과 성인여성간 PO를 제외한 모든 자세에서 통계적으로 유의한 차이를 나타냈다(p<.01) 푸리에지수는 낮은주파수(low, F1)에서 PO를 제외한 모든 자세에서 노인여성과 성인여성은 유의한 차이를 나타냈다(p<.01). 또한 중간낮은 주파수(middle-low, F2-F4), 중간높은주파수(middle-high, F5-F6), 높은주파수(high, F7-F8) 모두에서 노인여성이 성인여성보다 통계적으로 유의하게 높은 수치를 나타냈다. 모든 자세에서 노인여성의 체중분포율지수가 더 높게 나타났으나, PO와 PC에서만 통계적으로 유의했다. 이는 노화에 따른 생리학적 변화로 체성감각기관, 전정기관, 중추신경계등 전반적인 부분에서 능력이 저하됨에 따라 나타난 것으로 사료된다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권8호
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• pp.1946-1963
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• 2012

Hummingbird is a lightweight encryption and message authentication primitive published in RISC'09 and WLC'10. In FSE'11, Markku-Juhani O.Saarinen presented a differential divide-and-conquer method which has complexity upper bounded by $2^{64}$ operations and requires processing of few megabytes of chosen messages under two related nonces (IVs). The improved version, Hummingbird-2, was presented in RFIDSec 2011. Based on the idea of differential collision, this paper discovers some weaknesses of the round function WD16. Combining with the simple key loading algorithm, a related-key chosen-IV attack which can recover the full secret key is proposed. Under 15 pairs of related keys, the 128 bit initial key can be recovered, requiring $2^{27}$ chosen IV and the computational complexity is $O(2^{27})$. In average, the attack needs several minutes to recover the full 128-bit secret key on a PC. The experimental result corroborates our attack. The result shows that the Hummingbird-2 cipher can't resist related key attack.

• 복식
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• 제54권4호
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• pp.129-144
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• 2004

The modems who lives complicated society, the silence which the Orient thought asserts leads and to get comfortable. It is becoming, the like this social atmosphere will in the interest regarding a manual example and the Orient material, the use of the embroidery textile goods is increasing specially. The purpose of this article is to suggest a model for development of machine embroidery fabric material and highly value added apparel industries. The multi-headed embroidery machine where the application scope is wide from the dissertation, we are requested' NaNa company'. The multiheaded embroidery machine uses TAJIMA TMFD-G620 and SUNSTAR SWF-／B-WD(X) 620-100 the embroidery textile uses the silk, the cotton and the synthesis fertile goods etc 24 type, the embroidery thread Maraton thread(viscose rayon 100％) with used the cord. The 8 Korean motives are made on 23 fabrics, 6 of which are full-sized manufactured one-pieces and the other 17 of which are produced to home interior goods such as curtains or fashion accessories like handbags as simulations. Among the products, the pattern-4-1 and the pattern-4-2 are contracted with local fashion industry, and the pattern-1-1～3 are dealing with other companies in Japan. The computerized machine-embroidering and simulation producing of fashion items are available to reduce the cost in making samples and transfer the old labor ＆ toil-centered industry into the new technique ＆ knowledge centered one.

• KIEE International Transactions on Electrophysics and Applications
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• 제12C권4호
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• pp.201-207
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• 2002

A Pin-Cylinder discharge type ozonizer was designed and manufactured. The increase or decrease of temperature greatly influences on the characteristics of ozone generation of a discharge type ozonizer. The characteristics of ozone concentration ( $O_{3con}$), ozone generation ($_{3g}$) and ozone yield .ate ($_{3Y}$) of the ozonizer were investigated by varying the gas flow rate (Q), the discharge power ($_{Wd}$ ) and the temperature (T). At T = 20($^{\circ}C$), the values of ( $O_{3con}$) were found as 7800,5300,3000 and 2300(ppm) at Q=1,2,4 and 6(1/min) respectively. The corresponding values of ( $O_{3g}$) were found as 917, l247,1411 and 1623(mg/h) and those of ( $O_{3Y}$) were 93,126,143 and 164(g/kWh) respectively. When the temperature is decreased to -50($^{\circ}C$), the values of ( $O_{3con}$) became 12000,8000,5200 and 3600(ppm) at Q=1,2,4 and 6(1/min) respectively. The corresponding values of 0,9 were obtained as 1411,1882,2446 and 2600(mg/h) and those of ($O_{3Y}$) were 143,190,247 and 2631g/kWh] respectively. Hence as the temperature was decreased from 20 to -50[。C], the efficiencies of ozone generation were increased by 54,51,73 and 60[%] at Q=1,2,4 and 6(1/min) respectively.ctively.

• Journal of Biosystems Engineering
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• 제36권5호
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• pp.303-313
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• 2011

This study was conducted to investigate the effects of axle weight distribution and inflation pressure of tire on the fuel economy of tractors as well as operational range of tractor engine in terms of engine speed and power when a 4WD tractor of 38.2 kW rated power at 2500 rpm is used for plowing and flooded-field rotavating in paddy fields. (1) Plowing operation required an average engine power of 9.6~13.5 kW which equals 25~35% of rated PTO power. Engine speed ranged from 1,320.4 to 1,737.4 rpm, work velocity from 3.4 to 4.8 km/h, and fuel consumption from 3.2 to 4.2 L/h, respectively. (2) Flooded-field rotavating required an average engine power of 11.5~18.5 kW which equals 30~48.4% of rated PTO power. Out of this 6.2~12.2 kW was used for PTO power. Engine speed ranged from 1,557 to 2,067 rpm, work velocity from 2.5~5.4 km/h and fuel consumption from 3.2~5.5 L/h, respectively. (3) Axle weight distribution, inflation pressure of tire and moisture content of soil did not affect significantly the specific volumetric fuel consumption but affected significantly the fuel consumption per unit area of operation. Fuel savings amounted to 65% in plowing operation and 20% in flooded-field rotavating when the axle weight distribution and inflation pressure of tire were optimally adjusted. (4) Optimal adjustment of axle weight distribution and inflation pressure of tire are expected to save fuel consumption by 10~65% per unit area of operation in plowing and 10~20% in flooded-field rotavating.

• 한국수산과학회지
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• 제46권1호
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• pp.18-26
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• 2013

This study examined the taste, nutritional and functional characterizations of commercial seasoned sea squirt Halocynthia roretzi (CSS). Total taste values of CSS ranged from 7.6 to 69.5 and the major free amino acids were glutamic acid and aspartic acid. Total contents of amino acids in CSS ranged from 5.91 to 7.59 g/100 g and the major amino acids were also glutamic acid and aspartic acid. When taking 100 g of CSS, the minerals that could be expected to have functional health effects (minerals whose levels were above 10% of the recommended daily requirements) were P, Mg and Fe. Other minerals were also present in non-negligible quantities. In terms of the functional properties of CSS, ACE inhibitory activity was 21.2-37.1%, antioxidative activity was 55.4-90.4%, xanthine oxidase inhibitory activity was 52.9-76.6% and ${\alpha}$-glucosidase inhibitory activity was 0-32%. Antimicrobial activity against Vibrio parahaemolyticus was not detected, but activity against Staphylococcus aureus, groups such as KB, GG, CY, DN, HC and KH, and against Escherichia coli groups such as SF, WD, KB and GG, was detected.

• 미생물학회지
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• 제43권4호
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• pp.311-316
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• 2007

탄소원으로 thiodiglycol(TDG)을 함유한 배지에서 농후배양하여 인삼토양으로부터 TDG 분해균을 분리하였다. 분리균 WS-32의 형태적, 생화학적, 유전학적 특성을 조사한 결과 분리균이 Alcaligenes faecalis와 유사한 생화학적 성질을 지니고 있으며, 16S rRNA 서열이 Cupriavidus 속 균주와 유사도가 높은 균주로 판명되었다. WS-32는 $33^{\circ}C{\sim}37^{\circ}C$, pH $6.0{\sim}8.0$에서 성장이 우수하였으며, TDG에 의해 성장에 약간의 저해를 받지만, 배양후기에서는 이를 탄소원으로 이용하는 현상을 보였다. HPLC를 통해 배양액 내 잔존하는 TDG를 분석한 결과 2일 배양하였을 때 배지내 잔존하는 TDG가 상당량 감소한 것으로 확인되었다. 분리균 WD-32의 균체 파쇄상등액은 TDG의 산화활성을 보였으며, pH 8.0과 $45^{\circ}C$에서 산화활성이 가장 높았다.

• Journal of Biosystems Engineering
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• 제27권6호
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• pp.479-490
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• 2002

A dynamic model of a power shuttle transmission was developed and its validity was verified using the experimental data obtained from a transmission test bench. A 40㎾, 4WD tractor was also modeled using an application software EASY5 to investigate parameters and their effects on the power shifting performance. For a tractor model, the manual reverse gear was replaced by a power shuttle transmission. The tractor model also included an engine, main-gears for transmission, wheels, differentials and planet gears. Using the tractor model, the effects of the parameters such as modulating pressure and time, engine speed, tractor speed. tractor weight. reverse to forward speed ratio and torsional damper on the transient characteristics at starting and shuttle shifting were investigated by the computer simulation. The transient characteristics were represented by variations in clutch pressure, torque transmitted to input shaft and driving wheels, and power transmission capacity of the clutch. It was found that the modulating pressure and time affected most significantly the torque transmission and shifting time. The input torque, axle torque, power transmission capacity of the clutch and transmission time all increased with increase in engine speed, tractor speed. tractor weight and ratio of reverse to forward speeds. However, the axle torque decreased with tractor speed. Both the axle torque and power transmission capacity of the clutch also decreased with the ratio of reverse to forward speeds.

• 농업과학연구
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• 제51권2호
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• pp.133-146
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• 2024

Selection of gear reduction ratio is essential for machine design to ensure suitable power and speed during agricultural operations. The goal of the study was to evaluate the gear reduction ratio for a 1.6 kW four-wheel-drive (4WD) multi-purpose agricultural electric vehicle platform using workload data under different off-road conditions. A data acquisition system was fabricated to collect workload (torque) of the vehicle acting on the gear shaft. Field tests were performed under three driving surfaces (asphalt, concrete, and grassland), payload operations (981, 2,942, and 4,903 N), and slope conditions (0 - 4°, 4 - 8°, and 8 - 12°), respectively. Commercial speed reduction gear phases were attached to the input shaft of the vehicle powertrain. The maximum required torque was recorded as 37.5 Nm at a 4,903 N load with 8 - 12° slope levels, and the minimum torque was 12.32 Nm at 0 - 4° slope levels with a 981 Nm load for a 4 km/h speed on asphalt, concrete, and grassland roads. Based on the operating load condition and motor torque and rotational speed (TN) curve, the minimum and maximum gear reduction ratios were chosen as 1 : 50 and 1 : 64, respectively. The selected motor satisfied power requirements by meeting all working torque criteria with the gear reduction ratios. The chosen motor with a gear reduction ratio of 1 : 50 was suitable to fit with the motor T-N curve, and produced the maximum speeds and loads needed for driving and off-road activities. The findings of the study would assist in choosing a suitable gear reduction ratio for electric vehicle multi-purpose field operations.