• Title/Summary/Keyword: 6WD

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Improvement of Hill Climbing Ability for 6WD/6WS Vehicle using Optimum Tire Force Distribution Method (최적 타이어 힘 분배를 이용한 6WD/6WS 차량의 등판 주행 성능 향상)

  • Kim, Sang-Ho;Kim, Chang-Jun;Han, Chang-Soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.4
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    • pp.1523-1531
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    • 2011
  • Multi-axle driving vehicle are favored for military use in off road operations because of their high mobility on extreme terrains and obstacles. Especially, Military Vehicle needs an ability to driving on hills of 60% angle slope. This paper presents the improvement of the ability of hill climbing for 6WD/6WS vehicle through the optimal tire force distribution method. From the driver's commands, the desired longitudinal force, the desired lateral force, and the desired yaw moment were obtained for the hill climbing of vehicle using optimal tire force distribution method. These three values were distributed to each wheel as the torque based on optimal tire force distribution method using friction circle and cost function. To verify the performance of the proposed algorithm, the simulation is executed using TruckSim software. Two vehicles, the one the proposed algorithm is implemented and the another the tire's forces are equivalently distributed, are compared. At the hill slop, the ability to driving on hills is improved by using the optimum tire force distribution method.

Performance Evaluation of 6WD Military Vehicle Featuring MR Damper (MR 댐퍼를 적용한 6WD 군용차량의 성능평가)

  • Ha, Sung-Boon;Choi, Seung-Bok;Rhee, Eun-Jun;Kang, Pil-Soon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2008.11a
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    • pp.460-465
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    • 2008
  • This paper proposes a new type of MR (magentorheological) fluid based suspension system and applies it to military vehicle for vibration control. The suspension system consists of gas spring and MR damper. The nonlinear behavior of spring characteristics is evaluated with respect to the wheel travel and damping force model due to viscosity and yield stress of MR fluid is derived. Subsequently, a military vehicle of 6WD is adopted for the integration of the MR suspension system and its nonlinear dynamic model is establishes by considering vertical, pitch and roll motion. Then, a sky-hook controller associated with semi-active actuating condition is designed to reduce the vibration. In order to demonstrate the effectiveness of the proposed MR suspension system, computer simulation is undertaken showing vibration control performance such as roll angle and pitch angle evaluated under bump and random road profiles.

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Performance Evaluation of 6WD Military Vehicle Featuring MR Damper (MR댐퍼를 적용한 6WD 군용차량의 성능평가)

  • Ha, Sung-Hoon;Choi, Seung-Bok;Rhee, Eun-Jun;Kang, Pil-Soon
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.19 no.1
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    • pp.17-23
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    • 2009
  • This paper proposes a new type of MR(magnetorheological) fluid based suspension system and applies it to military vehicle for vibration control. The suspension system consists of gas spring and MR damper. The nonlinear behavior of spring characteristics is evaluated with respect to the wheel travel and damping force model due to viscosity and yield stress of MR fluid is derived. Subsequently, a military vehicle of 6WD is adopted for the integration of the MR suspension system and its nonlinear dynamic model is established by considering vertical, pitch and roll motion. Then, a sky-hook controller associated with semi-active actuating condition is designed to reduce the imposed vibration. In order to demonstrate the effectiveness of the proposed MR suspension system, computer simulation is undertaken showing vibration control performance such as roll angle and pitch angle evaluated under bump and random road profiles.

Comments on an Improved RFID Security Protocol for ISO/IEC WD 29167-6

  • Kang, You Sung;Choi, Dooho;Park, Dong-Jo
    • ETRI Journal
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    • v.35 no.1
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    • pp.170-172
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    • 2013
  • With the rapid progress of RFID security technologies, the international standard group ISO/IEC JTC 1/SC 31 is developing a few security technologies for RFID systems. One of the initial proposals is ISO/IEC working draft (WD) 29167-6. Recently, Song and others stated that Protocol 1 of ISO/IEC WD 29167-6 is vulnerable to a malicious adversary. However, their analysis comes from a misunderstanding regarding a communication parameter called Handle. In this letter, we point out that an adversary cannot obtain any sensitive information from intervening in Protocol 1.

Wilson's Disease in Bangladeshi Children: Analysis of 100 Cases

  • Rukunuzzaman, Md.
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.18 no.2
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    • pp.121-127
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    • 2015
  • Purpose: To evaluate clinical and laboratory profile of Wilson's disease (WD) in children. Methods: This cross sectional study was conducted at Bangabandhu Sheikh Mujib Medical University Hospital. Bangladesh, over a period of 3 years. One hundred consecutive children of WD between 3 to 18 years of age were evaluated. Results: Mean age was $8.5{\pm}1.5years$. Male female ratio was 2:1. Ninety-one percent of patients were Muslim and 9% Hindu. A total of 53% cases of hepatic WD presented between 5 to 10 years of age and most of the neurologic WD manifested in 10-15 years age group. Sixty-nine children presented only with hepatic manifestations, 6 only with neurological manifestations, 14 with both hepatic and neurological manifestation, 10 children was asymptomatic and 1 patient presented with psychiatric features. WD presented as chronic liver disease (CLD) in 42%, CLD with portal hypertension in 34%, acute hepatitis in 20% and fulminant hepatic failure in 4% cases. Stigmata of CLD were found in 18% patients. Keiser-Fleischser ring was found in 76% total patients. Elevated serum transaminase was found in 85% cases, prolonged prothrombin time in 59% cases and hypoalbuminaemia in 53% cases. A total of 73% patients had low serum ceruloplasmin, basal urinary copper of >$100{\mu}g/day$ was found in 81% cases and urinary copper following penicillamine challenge of >$1,200{\mu}g/day$ was found in 92% cases. Conclusion: Majority of studied WD children presented with hepatic manifestation of which 76% presented with CLD. Any child presented with jaundice after the age of 3 years should be investigated for WD.

A novel WD40 protein, BnSWD1, is involved in salt stress in Brassica napus

  • Lee, Sang-Hun;Lee, Jun-Hee;Paek, Kyung-Hee;Kwon, Suk-Yoon;Cho, Hye-Sun;Kim, Shin-Je;Park, Jeong-Mee
    • Plant Biotechnology Reports
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    • v.4 no.2
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    • pp.165-172
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    • 2010
  • Genes that are expressed early in specific response to high salinity conditions were isolated from rapeseed plant (Brassica napus L.) using an mRNA differential display method. Five PCR fragments (DD1.5) were isolated that were induced by, but showed different response kinetics to, 200 mM NaCl. Nucleotide sequence analysis and homology search revealed that the deduced amino sequences of three of the five cDNA fragments showed considerable similarity to those of ${\beta}$-mannosidase (DD1), tomato Pti-6 proteins (DD5), and the tobacco harpin-induced protein hin1 (DD4), respectively. In contrast, the remaining clones, DD3 and DD2, did not correspond to any substantial existing annotation. Using the DD3 fragment as a probe, we isolated a full-length cDNA clone from the cDNA library, which we termed BnSWD1 (Brassica napus salt responsive WD40 1). The predicted amino-acid sequence of BnSWD1 contains eight WD40 repeats and is conserved in all eukaryotes. Notably, the BnSWD1 gene is expressed at high levels under salt-stress conditions. Furthermore, we found that BnSWD1 was upregulated after treatment with abscisic acid, salicylic acid, and methyl jasmonate. Our study suggests that BnSWD1, which is a novel WD40 repeat-containing protein, has a function in salt-stress responses in plants, possibly via abscisic acid-dependent and/or -independent signaling pathways.

Behavioral and physiological changes during heat stress in Corriedale ewes exposed to water deprivation

  • Nejad, Jalil Ghassemi;Sung, Kyung-Il
    • Journal of Animal Science and Technology
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    • v.59 no.7
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    • pp.13.1-13.6
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    • 2017
  • This study was conducted to investigate the behavioral and physiological changes of heat stressed Corriedale ewes exposed to water deprivation. Nine Corriedale ewes (average $BW=45{\pm}3.7kg$) were individually fed diets based on maintenance requirements in metabolic crates. Ewes were assigned into three groups (9 sheep per treatment) according to a $3{\times}3$ Latin square design for 3 periods with 21-d duration for each period. The control (CON) group was given free access to water, 2 h water deprivation (2hWD), and 3 h water deprivation (3hWD) following feeding. No differences were found in fecal excretion frequency, standing frequency (number/d), and sitting frequency among the groups (p > 0.05). Measurements of standing duration (min/d) and urine excretion frequency (number/d) showed a significant decrease whereas sitting duration (min/d) showed a significant increase in the 2hWD and 3hWD groups when compared with the CON group (p < 0.05). Fecal score and heart rate (number/min) were not different among the groups (p > 0.05). However, respiratory rate (number/min) and panting score were found to be significantly higher in the 2hWD and 3hWD groups than in the CON group (p < 0.05). It is concluded that water deprivation following feeding intensifies physiological heat stress related indicators such as respiratory rate and panting score and changes behavioral parameters such as water intake and urine excretion frequency in heat stressed ewes. Daily adaptation to the extreme environmental conditions may occur actively in ewes.

Physiological Relationship Between Thirst Level and Feed Intake in Goats Fed on Alfalfa Hay Cubes

  • Prasetiyono, Bambang W.H.E.;Sunagawa, Katsunori;Shinjo, Akihisa;Shiroma, Sadao
    • Asian-Australasian Journal of Animal Sciences
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    • v.13 no.11
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    • pp.1536-1541
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    • 2000
  • The present study was carried out to measure changes of feed intake and thirst level caused by water deprivation in goats fed on dry feed and to elucidate the relationship between those two parameters. Water deprivation significantly (p<0.01) decreased cumulative feed intake and rate of eating at 30, 60, 90 and 120 min, respectively, after feed presentation. Cumulative feed intake, after completion of 2 h feeding, was reduced by about 20, 21 and 64 % due to water deprivation during feeding for 2 h (WD2), for 22 h (WD22) and for 46 h (WD46), respectively, compared to free access to water (FAW). Compared to the FAW, WD2, WD22 and WD46 increased thirst level by about 5, 5 and 9 times, respectively. Mean thirst level (X, g/30 min) was negatively correlated with cumulative feed intake (Y, g DM) after completion of 2h feeding (Y=1302-0.2 X, $r^2=0.97$, p<0.05). Water deprivation depressed plasma volume and there was a significant positive regression between plasma volume (X, ml) and cumulative feed intake (Y, g DM) after completion of 2h feeding (Y=-1003+0.6 X, $r^2=0.99$, p<0.01). Mean plasma osmolality (X, mOsmol/l) correlated significantly and negatively with cumulative feed intake (Y, g DM) after completion of 2h feeding (Y=27004-84.9 X, $r^2=0.95$, p<0.05). In conclusion, a decrease of feed intake during water deprivation is mainly due to an increase of thirst level quantitatively, and the act of feeding itself induces thirst more than the length of water-deprivation periods in goats fed on dry feeds. The present findings suggest that plasma osmolality and plasma volume which affect thirst level are involved in the decrease of feed intake in water-deprived goats.

A Study on Maneuvering Control Algorithm Based on All-wheel Independent Driving and Steering Control for Special Purpose 6WD/6WS Vehicles (전차륜 독립휠 구동 및 조향 제어 기반 특수목적용 6WD/6WS 차량의 주행제어 알고리즘 연구)

  • Lee, Daeok;Yeo, Seungtai
    • Journal of the Korea Institute of Military Science and Technology
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    • v.16 no.3
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    • pp.240-249
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    • 2013
  • This paper discusses the maneuvering control algorithm based on all-wheel independent driving and steering control techniques for special purpose 6WD/WS vehicles. The maneuvering control algorithms considering superior dynamic characteristics of high power in-wheel motors and independent steering system are designed to perform driving, steering, vehicle stability, and fault tolerant control. The maneuvering controller applies sliding and optimal control theories considering optimal torque distribution and friction circle related to the vertical tire force. The fault tolerant control algorithm is applied to obtain the similar maneuverability to that of the non-faulty vehicle. The simulations using the Matlab/Simulink dynamics model and experiments using HIL simulator mounting the real controllers with the designed control algorithms prove the improved performances in terms of vehicle stability and maneuverability.

Diagnostic Value of Ceruloplasmin in the Diagnosis of Pediatric Wilson's Disease

  • Kim, Jung Ah;Kim, Hyun Jin;Cho, Jin Min;Oh, Seak Hee;Lee, Beom Hee;Kim, Gu-Hwan;Choi, Jin-Ho;Kim, Kyung Mo;Yoo, Han-Wook
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.18 no.3
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    • pp.187-192
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    • 2015
  • Purpose: Measurement of serum ceruloplasmin level is the first step in screening for Wilson's disease (WD). Despite the rarity of WD in the general population, ceruloplasmin levels are routinely measured through hepatitis screening in both adults and children. Herein, we evaluated the diagnostic value of ceruloplasmin for the diagnosis of WD among children with hepatitis. Methods: We retrospectively reviewed data on serum ceruloplasmin levels measured as a serologic marker for patients with hepatitis at Asan Medical Center (Seoul, Korea) between from January 2004 to November 2013. The diagnosis of WD was confirmed by the identification of pathogenic variants in the ATP7B gene. To determine the diagnostic accuracy of ceruloplasmin, receiver operation characteristic (ROC) curves were constructed and the area under curve (AUC) were calculated. Results: Measurements of serum ceruloplasmin were performed in 2,834 children who had hepatitis. Among these, 181 (6.4%) children were diagnosed with WD. The sensitivity, specificity, and accuracy of a ceruloplasmin level of <20 mg/dL in the discrimination of WD were 93.4%, 84.2%, and 84.8%, respectively. In this study, 418 (14.7%) false-positive cases and 12 (0.4%) false-negative cases were noted. Using a ROC curve, a ceruloplasmin level of ${\leq}16.6mg/dL$ showed the highest AUC value (0.956) with a sensitivity of 91.2%, a specificity of 94.9%, and an accuracy of 94.7%. Conclusion: The measurement of serum ceruloplasmin was frequently used for the screening of WD in children, despite a low positive rate. The diagnostic value of ceruloplasmin may be strengthened by adopting a new lower cut-off level.