• Journal of Biosystems Engineering
• /
• v.42 no.3
• /
• pp.127-135
• /
• 2017

Purpose: Purpose: The usability of a mathematical model modified for analysis of the static stability of an asymmetric tractor-harvester system was investigated. Method: The modified asynchronous mathematical model was validated through empirical experiments, and the effects of movements of the center of gravity (CG) coordinates on the stability against lateral overturning were analyzed through simulations. Results: Changes in the lateral overturning angle of the system were investigated when the coordinates of the CG of the system were moved within the variable range. The errors between simulation results and empirical experiments were compared, and the results were -4.7% at the left side overturning and -0.1% at the right side overturning. The asymmetric system was characterized in such a way that the right side overturning had an increase in overturning angle in the (+) variable range, while it had a decrease in overturning angle in the (-) variable range. In addition, the left side overturning showed an opposite result to that of the right side. At the declination angle (296<${\gamma}$<76), the right side overturning had an increase in the maximum overturning angle of 3.6%, in the minimum overturning angle of 20.3%, and in the mean overturning angle of 15.9%. Furthermore, at the declination angle (284<${\gamma}$<64), the left side overturning had a decrease in the maximum overturning angle of 29.2%, in the minimum overturning angle of 44%, and in a mean overturning angle of 39.7%. Conclusion: The modified mathematical model was useful for predicting the overturning angle of the asymmetric tractor-harvester system, and verified that a movement of the CG coordinates had a critical effect on its stability. In particular, the left side overturning was the most vulnerable to stability, regardless of the direction of declination angle.

• 한국태양에너지학회:학술대회논문집
• /
• 2008.04a
• /
• pp.55-60
• /
• 2008

This study is on the analysis of power output of transparent thin-film PV windows which are integrated into the building envelope instead of traditional windows. 3 installation angles of vertical, horizontal and $30^{\circ}C$ inclination are investigated. To measure power output of PV windows, full scale mock-up house was designed and constructed. The power performance of PV window system was analyzed for horizontal angle, declination angle and vertical angle according to incline angle. Monitoring data are gathered from November 2006 to August 2007 and statistical analysis is performed to analysis a characteristics of power performance of transparent PV windows. Results show that annual power output of PV window with horizontal angle is 844.4kWh/kWp/year, declination angle 1,060kWh/kWp/year and vertical angle 431.6 kWh/kWp/year.

• Journal of Korean Foot and Ankle Society
• /
• v.17 no.2
• /
• pp.121-129
• /
• 2013

Purpose: To evaluate the radiographic characteristics of the tarsometatarsal osteoarthritis with hallux valgus deformity and report the clinical results of the operative treatment. Materials and Methods: This is a retrospective study of 20 patients, 22 feet who had been operated for non-traumatic tarsometatarsal osteoarthritis with hallux valgus (TMT group) and control group of hallux valgus patients without tarsometatarsal osteoarthritis (26 patients, 28 feet) from April 2004 to July 2011. Radiographic characteristics were compared between the groups, using hallux valgus angle, $1^{st}-2^{nd}$ intermetatarsal angle, metatarsal length ratio, metatarsus adductus angle, talonavicular coverage angle, talus-$1^{st}$ metatarsal angle, calcaneal pitch angle and medial cuneiform height. Pre- and postoperative difference of $1^{st}-2^{nd}$ metatarsal declination angle and distance between the $1^{st}-2^{nd}$ metatarsal head were evaluated. The clinical results were evaluated by American Orthopaedics Foot and Ankle Society (AOFAS) midfoot scale and visual analogue scale (VAS). Results: Metatarsal length ratio was significantly larger in TMT group (p<0.001). Metatarsus adductus angle, talonavicular coverage angle, talus-$1^{st}$ metatarsal angle on lateral radiograph, calcaneal pitch angle and medial cuneiform height were different from control group (p<0.001, p<0.001, p=0.001, p=0.010, p=0.006). Postoperative declination of the $2^{nd}$ metatarsal and distance between the $1^{st}-2^{nd}$ metatarsal head were increased (p=0.009, p=0.001). The AOFAS and VAS score were improved (p<0.001, p<0.001). Conclusion: Non-traumatic osteoarthritis of the tarsometatarsal joints seems to be associated with long 2nd metatarsal length, metatarsus adductus and flatfoot deformity. Spur excision may be successful to relieve symptoms when the arthritis was diagnosed in early stage.

• Advances in Energy Research
• /
• v.5 no.3
• /
• pp.227-237
• /
• 2017

The continuous increase of emission rates of green house gases and the effects on global warming added a new dimension to the problem of substituting the petroleum and its derivatives by environment friendly and sustainable energy sources for the world. Solar and wind energy appear at the top of the list of renewable of high potential, widely available, of dominated technology and well accepted. Brazil is one of the few countries in the world that receives number hours of sunshine exceeding 3,000 hours per year with a daily average of 4.5 to 6 kWh. However, this potential is largely unexplored and poorly tapped. The number of renewable systems implanted in Brazil has grown in recent years, but still insignificant when compared, for example, with Germany and Spain among others. This paper presents the results of an optical study on small concentration solar collector with evacuated tube enveloping the absorber and internal reflective surface fixed on the bottom part of the evacuated tube. The designed collector has a 2D geometrical concentration ratio between 2.455 and 4.91. The orientation of the solar collector, the ratio of the radius of the receiver to the radius of the absorber, the incidence angle for each period of the year, the collector inclination angle, the aperture angle of the reflective surface, concentration and optical efficiency were determined. The ray traces and flux distribution on the absorber of the evacuated tube solar collector were determined by using the program Ray Optics Simulation. The optical efficiency varies during the year according to the solar declination. For the periods were the solar declination is close to zero the efficiencies are maximum, and the variation during the day is around 25.88% and 99.9%. For the periods were the solar declination is maximum the efficiencies are minimum, and the variation during the day is around 23.78% and 91.79%.

• Korean Journal of Applied Biomechanics
• /
• v.29 no.2
• /
• pp.61-70
• /
• 2019

Objective: This study aimed to investigate the characteristics of the declination of the subtalar joint rotation axis and the structural features of the ankle joint complex such as rear-foot angle alignment and ligament laxity test between chronic ankle instability (CAI) patients and healthy control. Method: A total of 76 subjects and CAI group (N=38, age: $23.11{\pm}7.63yrs$, height: $165.67{\pm}9.54cm$, weight: $60.13{\pm}11.71kg$) and healthy control (N=38, age: $23.55{\pm}7.03yrs$, height: $167.92{\pm}9.22cm$, weight: $64.58{\pm}13.40kg$) participated in this study. Results: The declination of the subtalar joint rotation axis of the CAI group was statistically different from healthy control in both sagittal slope and transverse slope. The rear-foot angle of CAI group was different from a healthy control. Compared to healthy control, they had the structure of rear-foot varus that could have a high occurrence rate of ankle varus sprain. CAI group had loose ATFL and CFL compared to the healthy control. Conclusion: The results of this study showed that the deviation of the subtalar joint rotation axis and the structural features of the ankle joint complex were different between the CAI group and the healthy control and this difference is a meaningful factor in the occurrence of lateral ankle sprains.

• Korean Journal of Applied Biomechanics
• /
• v.21 no.4
• /
• pp.397-403
• /
• 2011

The purpose of this study is to analyze the immediate effects of five toed shoes on foot structure. Subjects consisted of 26 college-aged women with pes planus. X-ray analysis of student feet were performed both barefooted and with five toed shoes. Dependent variables were hallux valgus angle, calcaneal inclination angle, 1st metatarsal declination angle, and intermetartarsal angle. Independent t-test was used for statistical analysis along with SAS. Overall, there were statistically significant changes of test subject's dependent variables when wearing five toed shoes. Specifically, the hallux valgus angle decreased, the calcaneal inclination angle and 1st metatarsal inclination angle increased, and intermetatasal angles both increased and decreased, shifting towards normal range. In every case the dependent variables shifted towards a more normal range while subjects wore five toed shoes. This study only examined the immediate corrective effects of five toed shoes on foot structure, but long-term studies are needed to understand the prolonged effects of five toed shoes on foot structure.

• Journal of Ocean Engineering and Technology
• /
• v.23 no.1
• /
• pp.1-6
• /
• 2009

The paper describes results of a sensitivity study on an optimum mooring cost as a function of safety factor and allowable maximum offset of the offshore floating structure by finding the anchor leg component size and the declination angle. A harmony search (HS) based mooring optimization program was developed to conduct the study. This mooring optimization model was integrated with a frequency-domain global motion analysis program to assess both cost and design constraints of the mooring system. To find a trend of anchor leg system cost for the proposed sensitivity study, optimum costs after a certain number of improvisation were found and compared. For a case study a turret-moored FPSO with 3 ${\times}$ 3 anchor leg system was considered. To better guide search for the optimum cost, three different penalty functions were applied. The results show that the presented HS-based cost-optimum offshore mooring design tool can be used to find optimum mooring design values such as declination angle and horizontal end point separation as well as a cost-optimum mooring system in case either the allowable maximum offset or factor of safety varies.

• Journal of The Korean Astronomical Society
• /
• v.29 no.spc1
• /
• pp.399-400
• /
• 1996

LAMOST is a special reflecting Schmidt telescope. Both the refleting Schmidt plate $M_A$ and the spherical primary mitrror $M_B$ are segmened mirrors. These two cofocus but not co-phase. The diffraction of the optical system is decided by the shape overlapping of $M_A$ and $M_B$. This paper describes the diffraction caculating results with different declination and different field angle. The diffraction influence to the image quality is acceptable in the error buget of optical system. It also proves that the size seletion of the sub-mirror is reasonable.

• Journal of Korean Foot and Ankle Society
• /
• v.10 no.1
• /
• pp.66-70
• /
• 2006

Purpose: To analyze the clinical and radiological outcome of subtalar arthrodesis using cannulated screws and morselized bone graft. Materials and Methods: Twenty one patients with follow-up of more than 1 year after subtalar arthrodesis were included in this study. Mean age was 40.8 years, and mean follow-up duration was 38 months. Underlying diseases were 19 cases of posttraumatic arthritis (18 calcaneal fractures and 1 talar fracture) and 2 cases of tarsal coalition. Clinically AOFAS ankle-hindfoot score, operation time, complication and satisfaction of patients were analyzed. Radiologically time to union, arthritis of surrounding joints, preoperative and postoperative talar declination angle were analyzed. Results: AOFAS ankle-hindfoot score was improved from preoperative 33 points to postooperative 79 points. Eighteen patients (86%) were satisfied with the results. Mean operation time was 91 minutes. All cases were fixed with 1-2 cannulated screws and morselized bone graft. Mean time to radiologic union was 12.1 weeks. There was 1 case of delayed union. There was no significant perioperative changes in talar declination angles. Conclusion: Subtalar arthrodesis using cannulated screws and morselized bone graft seems to be relatively simple and effective treatment method for subtalar arthritis.

• Journal of Institute of Control, Robotics and Systems
• /
• v.8 no.1
• /
• pp.37-45
• /
• 2002

A method of measuring the length of defects on the wall and restructuring the defect image is proposed based on the estimation algorithm of a camera orientation, which uses the declination angle of a laser slit beam. The estimation algorithm of the horizontally inclined angle of CCD camera adopts a 3-dimensional coordinate transformation of the image plane where both the laser beam and the original image of the defects exist. The estimation equation is obtained by using the information of the beam projected on the wall and the parameters of this equation are experimentally obtained. With this algorithm, the original image of the defect can be reconstructed as an image normal to the wall. From the result of a series of experiments, the measuring accuracy of the defect is measured within 0.5% error bound of real defect size under 30 degree of the horizontally inclined angle. The proposed algorithm provides the method of reconstructing the image taken at any arbitrary horizontally inclined angle as the image normal as the wall and thus, it enables the accurate measurement of the defect lengths by using a single camera and a laser slit beam.