• Journal of Ocean Engineering and Technology
• /
• v.11 no.1
• /
• pp.10-15
• /
• 1997

Copper and its alloy had been used widely because of its pronouncing characteristics on their high thermal and electrical conductivity. Various fusion welding methods, such as SMAW, SAW, GTAW, GMAW, Electroslag welding amd so on are applied to weld copper and its alloy. But fusion welding of copper has so many welding problems. THe most serious problems were poor penetration amd high thermal contration stress due to its high thermal conductivity and porosity could be formed by rapid cooling rate of fusion welding. In order to avoid such fusion welding problems, preheating, peering and heat treatment must be applied to obtain sound weld joint of copper. But preheating induce another welding problem such as grain coarsening of weld heat affected zone. This grain coarsening reduces ductility and strength of weld joint. In this view of point, friction welding of copper is triedm to obtain sound weld joint of copper by reducing metallurgical problems. This study introduced new concept of heat input for evaluating the friction weldability of copper. As a result, weldability of copper could be evaluated by this new concept of heat input.

• Journal of Institute of Control, Robotics and Systems
• /
• v.17 no.6
• /
• pp.546-551
• /
• 2011

Tilt sensor is required to control the attitude of the biped robot when it walks on an uneven terrain. Vision sensor, which is used for recognizing human or detecting obstacles, can be used as a tilt angle sensor by comparing current image and reference image. However, vision sensor alone has a lot of technological limitations to control biped robot such as low sampling frequency and estimation time delay. In order to verify limitations of vision sensor, experimental setup of an inverted pendulum, which represents pitch motion of the walking or running robot, is used and it is proved that only vision sensor cannot control an inverted pendulum mainly because of the time delay. In this paper, to overcome limitations of vision sensor, Kalman filter for the multi-rate sensor fusion algorithm is applied with low-quality gyro sensor. It solves limitations of the vision sensor as well as eliminates drift of gyro sensor. Through the experiment of an inverted pendulum control, it is found that the tilt estimation performance of fusion sensor is greatly improved enough to control the attitude of an inverted pendulum.

• Korean Journal of Remote Sensing
• /
• v.28 no.6
• /
• pp.611-622
• /
• 2012

This study proposed two multisensor fusion methods for segment-based image classification utilizing a region-growing segmentation. The proposed algorithms employ a Gaussian-PDF measure and an evidential measure respectively. In remote sensing application, segment-based approaches are used to extract more explicit information on spatial structure compared to pixel-based methods. Data from a single sensor may be insufficient to provide accurate description of a ground scene in image classification. Due to the redundant and complementary nature of multisensor data, a combination of information from multiple sensors can make reduce classification error rate. The Gaussian-PDF method defines a regional measure as the PDF average of pixels belonging to the region, and assigns a region into a class associated with the maximum of regional measure. The evidential fusion method uses two measures of plausibility and belief, which are derived from a mass function of the Beta distribution for the basic probability assignment of every hypothesis about region classes. The proposed methods were applied to the SPOT XS and ENVISAT data, which were acquired over Iksan area of of Korean peninsula. The experiment results showed that the segment-based method of evidential measure is greatly effective on improving the classification via multisensor fusion.

• The Korean Journal of Zoology
• /
• v.29 no.4
• /
• pp.235-244
• /
• 1986

In order to elucidate the effect of neurotransmitter on the differention of myoblasts in vitro, dopamine was administered to the myoblasts at varying stages of myogenesis, and the fusion index, the rate of creatine kinase (CK) synthesis, and the sensitivity to dopamine were determined. When dopamine $(3 \\times 10^{-5} M)$ was administered at 34 hr after myoblast seeding, a significant decrease in the fusion index as well as CK synthesis was observed, indicating a good correlation exists between these two parameters. In other experiment, dopamine was administered at varying stages of myogenesis and the inhibitory effect of dopamine as scored by fusion index at 96 hr was found to be cyclic in nature. This finding raised a possibility that arrangement of dopamine receptors occurs according to the cell cycle stages in myogenesis.

• Nuclear Engineering and Technology
• /
• v.54 no.10
• /
• pp.3703-3716
• /
• 2022

Target alignment technology is one of the most critical technologies in laser fusion experiments and is an important technology related to the success of laser fusion experiments. In this study, by combining the open-loop and closed-loop errors of the target alignment, the Kalman state observer is used to estimate the position of the target, which improves the observation precision of the target alignment. Then the optimized result is used to guide the alignment of the target. This method can greatly optimize the target alignment error and reduce uncertainty. With the improvement of the target alignment precision, it will greatly improve the reliability and repeatability of the experiments' results, thereby improving the success rate of the experiments.

• International Journal of Computer Science & Network Security
• /
• v.23 no.11
• /
• pp.67-72
• /
• 2023

In the past decade, Autonomous Vehicle Systems (AVS) have advanced at an exponential rate, particularly due to improvements in artificial intelligence, which have had a significant impact on social as well as road safety and the future of transportation systems. The fusion of light detection and ranging (LiDAR) and camera data in real-time is known to be a crucial process in many applications, such as in autonomous driving, industrial automation and robotics. Especially in the case of autonomous vehicles, the efficient fusion of data from these two types of sensors is important to enabling the depth of objects as well as the classification of objects at short and long distances. This paper presents classification of objects using CNN based vision and Light Detection and Ranging (LIDAR) fusion in autonomous vehicles in the environment. This method is based on convolutional neural network (CNN) and image up sampling theory. By creating a point cloud of LIDAR data up sampling and converting into pixel-level depth information, depth information is connected with Red Green Blue data and fed into a deep CNN. The proposed method can obtain informative feature representation for object classification in autonomous vehicle environment using the integrated vision and LIDAR data. This method is adopted to guarantee both object classification accuracy and minimal loss. Experimental results show the effectiveness and efficiency of presented approach for objects classification.

• Journal of Korean Foot and Ankle Society
• /
• v.8 no.1
• /
• pp.31-38
• /
• 2004

Purpose: The purpose of the study was to identify the subtypes of idiopathic osteoarthritis of the tarsometatarsal joints based on accompanying hindfoot, midfoot, or foot deformities and their corresponding surgical options and also to evaluate the overall clinical results. Materials and Methods: The study included 59 patients (67 feet) with idiopathic tarsometatarsal joint osteoarthritis. Tarsometatarsal fusion was performed for tarsometatarsal joint and accompanied secondary change was divided into subtypes and various bony reconstruction was carried out. The patients were evaluated with the AOFAS midfoot score and FFI. The average patient age was 60.2 years with 40.6 months follow-up. Fifty-four feet (80.6%) had been treated with realignment fusion. Twenty-six feet had first and second tarsometatarsal joint fusion, and 20 feet had first tarsometatarsal fusion only. Six subtypes were identified based on associated foot deformities: 1) in-situ without deformities (18%), 2) pes planovalgus (45%), 3) rockerbottom (15%), 4) cavus foot (1%), 5) hallux valgus (12%), and 6) hallux valgus with pes planovalgus or rockerbottom (9%). Plantar-medial closing-wedge resection was used in 10 feet to correct rockerbottom. For pes planovalgus, a medial sliding calcaneal osteotomy was done. Lateral column lengthening with medial sliding calcaneal osteotomy was done for severe pes planovalgus, and triple arthrodesis was done for rigid pes planovalgus. Hallux valgus was corrected with the Lapidus procedure (85.7%). Results: AOFAS midfoot scores improved from preoperative 34.1 points to postoperative 83.9 points (p<0.05). The Foot Function Index postoperatively also showed significant improvement (p<0.05), with a high satisfaction rate (86.6%). There were 29 complications, most commonly sesamoid pain. Conclusion: Idiopathic tarsometatarsal OA feet can be classified into six categories. Pes planovalgus feet should be treated with medial sliding calcaneal osteotomy, lateral column lengthening, or triple arthrodesis in addition to tarsometatarsal joint realignment fusion. Rockerbottom and hallux valgus deformities should also be addressed.

• Journal of Korean Neurosurgical Society
• /
• v.29 no.8
• /
• pp.1043-1049
• /
• 2000

Objective : This study was undertaken to evaluate the availability of allogenic fibular bone graft filled with autogenous bone dust in anterior cervical fusion after cervical discectomy. Methods : During a 4-year period(1995-1998), twenty four cases of anterior cervical fusion after discectomy were performed with fibular allograft filled with autogenous bone dust in degenerative cervical disease. We used freeze-dried fibular allograft and autogenous bone dust. Autogenous bone dust obtained from spondylotic spurs, osteophytes, and during foraminotomy. Cervical plating system was done at 8 patients. 5 patients were 1 level and 3 patients were 2 levels. All patients were routinely evaluated after surgery at 2 weeks, 1 month, 3 months, 5 months and 12 months. Mean follow-up period was 21months. Results : Eighty eight percent of the patients were found to have excellent or good clinical results. Radiographic follow-up revealed that 92% of the patients obtained complete or partial union by 5 months after surgery. One patient had graft extrusion immediately after surgery and had the graft reinserted. Two patients had longitudinal graft fractures. There were no graft related complications. Conclusion : Fibular allograft filled with autogenous bone dust for cervical interbody fusion after discectomy is an ideal graft material by showing obvious benefits of good fusion rate and elimination of donor site complications. And also we were able to obtain satisfactory clinical outcome.

• Journal of Korean Neurosurgical Society
• /
• v.51 no.3
• /
• pp.135-140
• /
• 2012

Objective : To evaluate radiographic results of anterior fusion methods in two-level cervical disc disease : tricortical autograft and plate fixation (ACDF-AP), cage and plate fixation (ACDF-CP), stand-alone cage (ACDF-CA), and corpectomy and plate fixation (ACCF). Methods: The numbers of patients were 70 with a minimum 6 month follow-up (ACDF-AP : 12, ACDF-CP : 27, ACDF-CA : 15, and ACCF : 16). Dynamic simple X-ray and computed tomography were evaluated preoperatively, postoperatively, 6 month, and at the final follow-up. The fusion and subsidence rates at the final were determined, and global cervical lordosis (GCL), cervical range of motion, fused segment angle (FSA), and fused segment height (FSH) were analyzed. Results: Nonunion was observed in 4 (25%) patients with ACDF-CA, 1 (8%) patient with ACDF-AP, 1 (4%) patient with ACDF-CP. The number of loss of FSH (%) more than 3 mm were 2 patients (16%) in ACDF-AP, 3 patients (11%) in ACDF-CP, 5 patients (33%) in ACDF-CA, and 3 patients (20%) in ACCF. The GCL was decreased with ACDF-CA and increased with others. The FSA was increased with ACDF-AP, ACDF-CP, and ACCF, but ACDF-CA was decreased. At the final follow-up, the FSH was slightly decreased in ACDF-CP, ACDF-AP, and ACCF, but ACDF-CA was more decreased. Graft related complication were minimal. Screw loosening, plate fracture, cage subsidence and migration were not identified. Conclusion: ACDF-CP demonstrated a higher fusion rate and less minimal FSH loss than the other fusions in two-level cervical disc disease. The ACDF-AP and ACCF methods had a better outcome than the ACDF-CA with respect to GCL, FSA, and FSH.

• Reproductive and Developmental Biology
• /
• v.33 no.1
• /
• pp.13-18
• /
• 2009

The aim of this study was to examine the microtubule distributions of somatic cell nuclear transfer (SCNT) and parthenogenetic porcine embryos. Porcine SCNT embryos were produced by fusion of serum-starved fetal fibroblast cells with enucleated oocytes. Reconstituted and mature oocytes were activated by electric pulses combined with 6-dimethlyaminopurine treatment. SCNT and parthenogenetic embryos were cultured in vitro for 6 days. Microtubule assembly of embryos was examined by confocal microscopy 1 hr and 20 hr after fusion or activation, respectively. The proportions of embryos developed to the blastocyst stage were 25.7% and 30.4% in SCNT and parthenogenetic embryos, respectively. The frequency of embryos showing $\beta$-tubulins was 81.8% in parthenogenetic embryos, whereas 31.3% in SCNT embryos 1 hr after activation or fusion. The frequency of the embryos underwent normal mitotic phase was low in SCNT embryos (40.6%) compared to that of parthenogenetic ones (59.7%) 20 hr after fusion or activation (p<0.05). The rate of SCNT embryos with an abnormal mitosis pattern is about twice compared to that of parthenogenetic ones. The spindle assembly and its distribution of SCNT embryos in the first mitotic phase were not different from those of parthenogenetic ones. The result shows that although microtubule distribution of porcine SCNT embryos shortly after fusion is different from parthenogenetic embryos, and the frequency of abnormal mitosis 20 hr after fusion or activation is slightly increased in SCNT embryos, microtubule distributions at the first mitotic phase are similar in both SCNT and parthenogenetic embryos.