• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.40 no.2
• /
• pp.133-138
• /
• 2016

Force control and collision detection for a robot are usually conducted using a 6-axis force/torque sensor mounted at the end-effector. However, this scheme suffers from high-cost and the inability to detect collisions at the robot body. As an alternative, joint torque sensors embedded in each joint were used, which also suffered from various errors in torque measurement. To resolve this problem, a robot joint module with an improved joint torque sensor is proposed in this study. In the proposed torque sensor, a cross-roller bearing and disk-type coupling are added to prevent the moment load from adversely affecting the measurement of the joint torque under consideration. This joint design also aims to reduce the stress induced during the assembly process of the sensor. The performance of the proposed joint torque sensor was verified through various experiments.

• Journal of the Korean Society for Advanced Composite Structures
• /
• v.5 no.3
• /
• pp.17-22
• /
• 2014

Fiber reinforced plastic (FRP) structural shapes are readily available in civil engineering applications. Among many manufacturing techniques used for FRP structural shapes, pultrusion process is one of the most widely used techniques in civil engineering applications. Pultrusion is a manufacturing process for producing continuous lengths of reinforced polymeric plastic structural shapes with constant cross-section. Pultruded composites are attractive for structural applications because of their continuous mass production with excellent mechanical properties. This paper presents the results of investigations pertaining to the bolted connection with two bolts for the pultruded FRP (PFRP) structural members. PFRP bolted connection tests were conducted with end distance to bolt diameter ratio ($e_1/d_b$) and two types of bolt pattern such as horizontal (Pattern A) and vertical arrangement (Pattern B). As a result, it is found that the $e_1/d_b$ is recommended as the ratio of 4. In addition, it is also found that the bearing strengths at failure of the Pattern A and Pattern B have a similar value.

• Journal of the Mineralogical Society of Korea
• /
• v.27 no.4
• /
• pp.197-205
• /
• 2014

Study area (Jikjeon-ri) is located in south end of the Hadong anorthositic rocks. And along the south-western boundary, diorite intruded the Hadong anorthosite. Ilmenite ore bodies are extended in both anorthosite and diorite. And their occurrence in the diorite are not studied yet. While no particular textures are found in the ilmenite within the anorthosite, the ilmenite within the diorite shows characteristic exsolution texture, that is, ilmenite phases are separated into rutile and Fe-oxide and the ilmenite and Fe-oxide. MnO composition in ilmenite ratios are 2.14~3.74wt%, it has higher composition in diorite than that in anorthosite. The plagioclase composition display andesine ($An_{28.7-42.9}$) in the diorite and labradorite ($An_{57.1-72.8}$) in the anorthosite in composition. The exsolution of ilmenite has been developed during the cooling of partly melted ilmenite into rutile and Fe-oxides which is related to the intrusion of the diorite.

• Journal of Positioning, Navigation, and Timing
• /
• v.6 no.4
• /
• pp.195-203
• /
• 2017

A 2U cube satellite called SNUGLITE has been developed by GNSS Research Laboratory in Seoul National University. Its main mission is to perform actual operation by mounting dual-frequency global positioning system (GPS) receivers. Its scientific mission aims to observe space environments and collect data. It is essential for a cube satellite to control an Earth-oriented attitude for reliable and successful data transmission and reception. To this end, an attitude estimation and control algorithm, Attitude Determination and Control System (ADCS), has been implemented in the on-board computer (OBC) processor in real time. In this paper, the Extended Kalman Filter (EKF) was employed as the attitude estimation algorithm. For the attitude control technique, the Linear Quadratic Gaussian (LQG) was utilized. The algorithm was verified through the processor in the loop simulation (PILS) procedure. To validate the ADCS algorithm in the ground, the experimental verification via a single axis Hardware-in-the-loop simulation (HILS) was used due to the simplicity and cost effectiveness, rather than using the 3-axis HILS verification (Schwartz et al. 2003) with complex air-bearing mechanism design and high cost.

• Journal of Acupuncture Research
• /
• v.21 no.5
• /
• pp.137-147
• /
• 2004

Objective : The aim of the study was to compare the therapeutic effect of the superficial and in-depth insertion of acupuncture needles in the treatment of patients with ankle sprain. Design : A prospective randomized single-blind study of superficial and deep acupuncture was conducted. Setting : The study was conducted in the Kang-nam Oriental Hosp. of Dong-Guk University. Patients: The study comprised 14 patients with ankle sprain who were divided into two groups (A and B). Intervention : In group A, the needle was introduced in the skin at a depth of 2 mm, whereas in group B the needle was placed deeply into muscular tissue or the articular capsule at a depth more than 1.5 Cm The treatment was planned for a duration of 1 week, 3 times. Outcome Measures : The intensity of pain was evaluated with the Ankle grade pain chart(AGPC) before and after treatment and at the 1-week follow-up examination. The AGPC includes Swelling, Tenderness, Exudation, Bruise, Medial/Lateral. stability test, Anterior drawer test, Squeeze test, Bearing weight, Pressure Algometer, Walking state and VAS. Results : Although at the end of the treatment there was no evidence of significant statistical differences between the two different groups, Pain reduction(VAS) was greater in the group treated with deep acupuncture. A statistical difference existed between the two groups at the 1 week follow up, with a better result in the deeply stimulated group in VAS. Conclusion : Clinical results show that deep stimulation has a better analgesic effect when compared with superficial stimulation in pain reduction(VAS, Visual analogic scale).

• Journal of Korean Medicine Rehabilitation
• /
• v.24 no.2
• /
• pp.51-64
• /
• 2014

Objectives This study was carried out to know the effects of Keonbodan (hereinafter referred to KBD) in osteoarthritis induced by Monosodium iodoacetate(hereinafter referred to MIA) on Wistar rat. Methods Osteoarthritis was induced by injection of MIA into left knee joint cavities of rat. Osteoarthritis rats were divided into 4 groups (normal (n=6), control (n=6), indomethacin (n=6), KBD (n=6) group). The control group was administered normal saline and indomethacin group was administered indomethacin (2 mg/kg). And the KBD group was administered KBD (142 mg/kg). Each groups were administered by orally for 4 weeks. This experiment were carried out in vivo. In vivo, at the end of the experiment (5 weeks after MIA injection), effects on hepatotoxicity and nephrotoxicity, cytokines in serum, arachidonic acid, osteocalcin, MMP-9, TIMP-1 and cartilage volume were evaluated. And histopathological examinations on the articular structures of knee joints were performed. Results 1. In weight-bearing measurement, level of weight was increased. 2. In order to hepatotoxicity and nephrotoxicity, ALT, AST, BUN and creatinine were tested. And there were no significant changes. 3. In serum, levels of TNF-$\alpha$, IL-$1{\beta}$ were significantly decreased. IL-6 was insignificantly decreased. 4. In serum, level of MMP-9 and TIMP-1 was decreased. 5. In serum, level of $LTB_4$, $PGE_2$ and osteocalcin was decreased. 6. In ${\mu}$CT-arthrography, the cartilage volume was greater than that of the control group. 7. The joint damage induced by osteoarthritis was lesser than the control group in histopathologic observation (H&E, Safranin-O staining). Conclusions These results demonstrated that KBD suppressed the osteoarthritis- inducing effects of MIA in rat. And further studies are required to find out more effective substance and anti-osteoarthritic mechanism in the future.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.11a
• /
• pp.855-858
• /
• 2008

A compression lap splice can be calculated longer than a tension lap splice in high strength concrete according to current design codes. Including effects of transverse reinforcement, a compression splice becomes much longer than a tension splice. Effects of transverse reinforcement on strength and behavior of compression lap splice, which always exist in actual structures, have been investigated through experimental study of column tests with concrete strength of 40 and 60 MPa. Confined specimens have twice of calculated strengths by current design codes. New design equations for the compression lap splice including the effects of transverse reinforcement are required for practical purpose of ultra-high strength concrete. End bearing is enhanced by transverse reinforcement placed at ends of splice not by transverse reinforcement within splice length. As more transverse reinforcement are placed, the stresses developed by bond linearly increase. The transverse reinforcements at ends of splice a little improve the strength by bond.

• Korean Journal of Clinical Pharmacy
• /
• v.17 no.1
• /
• pp.38-45
• /
• 2007

Background: The multitude of the therapeutic usefulness of intra-articular injection of hyaluronate on oateoarthritis of the knee is still in question. The objective of this systemic review was to elucidate both the therapeutic efficacy and the safety of intra-articular administration of hyaluronic acid for degenerative osteoarthritis of the knee joints. Methods: I searched MEDLINE and Korea Medical Database (KMbase) from January 1990 to April 2007 using a combination search terms for knee osteoarthritis and hyaluronic acid and a filter for randomized controlled trials. I extracted data on pain at rest, and during or just after movement, on joint function, and on adverse events. Results: Ten trials that reported usable quantitative information on any of the predefined end points were identified and included in the systemic review. Intra-articular injection of hyaluronic acid can decrease symptoms of osteoarthritis of the knee. The study revealed significant improvements in pain and functional outcomes with few adverse effects. However, there was significant between-study heterogeneity in the estimates of the efficacy of hyaluronic acid. Sub-group analysis showed that lower methodological quality such as a single-blind or single-center design resulted in higher estimates hyaluronic acid efficacy, and that patients older than sixty years of age and those with the most advanced radiographic stage of osteoarthritis were less likely to benefit from intra-articular injection of hyaluronic acid. Conclusion: According to the currently available evidence, intra-articular hyaluronic acid has been proven clinically effective for the patients bearing the knee osteoarthritis with NSAID-induced GI troubles or inapplicable to any surgery, and may be associated with lower risk of adverse events.

• Parasites, Hosts and Diseases
• /
• v.55 no.3
• /
• pp.341-345
• /
• 2017

The metacercariae of Artyfechinostomum malayanum (Leiper, 1911) Mendheim, 1943 were discovered in Pila sp. snails purchased from a market in Phnom Penh, Cambodia. They were isolated from the snails using the artificial digestion technique and were orally fed to 2 hamsters, 1 rat, and 2 mice to obtain the adult flukes. The metacercariae were round, $145-165{\mu}m$ in diameter, having a cyst wall of $6-10{\mu}m$ in thickness, a head collar and collar spines, and characteristic features of excretory granules. Adult flukes were recovered in the small intestines of the animals at days 14 and 32 post infection and were morphologically observed using a light microscope and a scanning electron microscope. They were plump or elongated, ventrally curved, $6.0-8.1{\times}1.6-2.0mm$ in size, and characterized by the head collar bearing 43 collar spines, including 5 end group ones on each side, a long cirrus sac extending beyond the posterior margin of the ventral sucker, a submedian ovary, and 2 deeply lobed testes. Eggs in uteri were operculate, ovoid to ellipsoid, and $120-135{\times}68-75{\mu}m$ in size. In scanning electron microscopy, the head collar was prominent with collar spines looking like horns. Scale-like tegumental spines were densely distributed on the ventral surface between the head collar and ventral sucker. Sensory papillae were distributed mainly on the tegument around suckers. By this study, it has been first confirmed that the life cycle of A. malayanum exists in Cambodia.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.5 no.3
• /
• pp.1-8
• /
• 2001

Seismic design forces for bridge components may be determined by modifying elastic member forces of design earthquakes using appropriate response modification factors according to the national design code of bridges Modeling technique of pile foundation system is one of the important parameters which greatly affects the results in the process of the elastic seismic analysis of a bridge system with pile foundation. In this paper, a approximate and simplified modeling technique of a pile foundation system for the practical purposes is presented. The modeling technique is based on the stiffnesses of pile foundation during earthquake. The horizontal stiffnesses are determined from the resistance-deflection curves derived from the results of dynamic field tests using cyclic loads and the vertical stiffness includes the effects of the end bearing capacities and side friction of piles as well as the pile compliances under the expected vertical load level. The applicability of the proposed technique has been validated through the some example bridge analyses.