• Journal of the Korean Society for Precision Engineering
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• v.15 no.6
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• pp.159-166
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• 1998

The problem of interface crack in the bonded structures has received a great deal of attention in recent years. In this paper the aluminum bonded single lap-joint containing the interface edge crack is investigated. The tensile load and the average shear stress of the adhesive joints which have different crack length are obtained from the static tensile tests. The critical value of crack length to provoke the interface fracture is determined to a/L=0.4, where a is the interface crack length and L is the adhesive lap-length. The fracture mechanical parameters are introduced to confirm the existence of the critical crack length. The compliance and the stress intensity factors are calculated using the displacement and the stress near the interface crack tip by the boundary element method. These numerical results support the experimental results that the critical value of a/L is 0.4. It is known that the compliance and the stress intensity factors are the efficient parameters to estimate the bonded single lap-joint containing the interface edge crack.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.7
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• pp.2339-2355
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• 2021

In this paper, a joint probabilistic data association algorithm based on loss function (LJPDA) is proposed so that the computation load and accuracy of the multi-target tracking algorithm can be guaranteed simultaneously. Firstly, data association is divided in to three cases based on the relationship among validation gates and the number of measurements in the overlapping area for validation gates. Also the contribution coefficient is employed for evaluating the contribution of a measurement to a target, and the loss function, which reflects the cost of the new proposed data association algorithm, is defined. Moreover, the equation set of optimal contribution coefficient is given by minimizing the loss function, and the optimal contribution coefficient can be attained by using the Newton-Raphson method. In this way, the weighted value of each target can be achieved, and the data association among measurements and tracks can be realized. Finally, we compare performances of LJPDA proposed and joint probabilistic data association (JPDA) algorithm via numerical simulations, and much attention is paid on real-time performance and estimation error. Theoretical analysis and experimental results reveal that the LJPDA algorithm proposed exhibits small estimation error and low computation complexity.

• Korean Journal of Child Studies
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• v.34 no.2
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• pp.1-25
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• 2013

The purpose of this study was to examine the relationship among infants' nonverbal communication, maternal verbal behaviors and the infants' acquisition of vocabulary. The subjects were 93 pairs of 10 to 18 months old infants and their mothers residing in the Seoul and GyeongGi-Do area. The results were as follows : (1) In terms of the infants' nonverbal communicative means, it appeared that the group of 16~18 month olds utilized more gesture and vocalization. As regards the infants' nonverbal communicative functions in terms of social behavior and joint attention, the group of 16~18 month olds was found to perform more of the behaviors from this category than the other groups. There was a significant difference in the maternal verbal behavior among the different age groups. (2) Among the infants' nonverbal communicative means, gesture and vocalization, there appeared to be a significant relationship between vocalization and the infants' acquisition of vocabulary. In addition, there was an important relationship between the high usage of infants' nonverbal communicative functions with behavior regulation and the high usage of joint attention and the successful acquisition of vocabulary among infants. (3) Social play, which is a maternal verbal behavior categorized as one of the strategies for getting infants' attention, was significantly related to the acquisition of infants' vocabulary. (4) When mothers used more imitating sounds and mimetic words, requests for information, descriptions, conventional social expressions, and imitation to enhance responsiveness, infants were found to have acquired a larger vocabulary.

• Smart Structures and Systems
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• v.12 no.3_4
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• pp.415-426
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• 2013

Condition assessment and monitoring of bridges is critical for safe passenger travel, public transportation, and efficient freight. In monitoring, displacement measurement capability is important to keep track of performance of bridge, in part or as whole. One of the most important parts of a bridge is the expansion joint, which accommodates continuous cyclic thermal expansion of the whole bridge. Though expansion joint is critical for bridge performance, its inspection and monitoring has not been considered significantly because the monitoring requires long-term data using cost intensive equipment. Recently, a wireless smart sensor network (WSSN) has drawn significant attention for transportation infrastructure monitoring because of its merits in low cost, easy installation, and versatile on-board computation capability. In this paper, a rapid wireless displacement monitoring system, wireless hybrid sensor (WHS), has been developed to monitor displacement of expansion joints of bridges. The WHS has been calibrated for both static and dynamic displacement measurement in laboratory environment, and deployed on an in-service highway bridge to demonstrate rapid expansion joint monitoring. The test-bed is a continuous steel girder bridge, the Founders Bridge, in East Hartford, Connecticut. Using the WHS system, the static and dynamic displacement of the expansion joint has been measured. The short-term displacement trend in terms of temperature is calculated. With the WHS system, approximately 6% of the time has been spent for installation, and 94% of time for the measurement showing strong potential of the developed system for rapid displacement monitoring.

• Tuberculosis and Respiratory Diseases
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• v.49 no.2
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• pp.162-168
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• 2000

Background : Joint symptoms frequently occur in the course of antituberculous chemotherapy and tend to be ignored and overlooked, but in some cases, they are often very troublesome in obstructing ordinary life. Joint symptoms that develop during antituberculous chemotherapy need to be understood, but there are few materials describing them systematically. Method : This study enrolled 33 patients with tuberculosis treated with first line antituberculous agents for more than 6months. In the course of treatment, joint symptoms not associated with specific cause, such as preexisting joint disease or trauma, were investigated and compared with thæe of the asymptomatic group. We confirmed the incidence of joint symptoms and factors associated with them. Results : Nineteen of 33 patients (58%) had joint symptoms. Joint symptoms developed 1.9$\pm$1.4 months after the beginning of chemotherapy and lasted for 3.6$\pm$2.5months. In 18 of 19 symptomatic patients, multiple joints were involved: shoulder (10 patients, 53%), knee (10, 53%), finger (6, 32 %). Joint symptoms were expressed as pain (19 patiens, 100%), stiffness (7, 37%) and/or swelling (3, 16%). Fourteen patients (74%) took analgesics to relieve their symptoms and in 2 patients, antituberculous agents were discontinued because of the severity of their symptoms. The symptoms seem to be caused by agents other than pyrazinamide, but it was very difficult to identify the definite causative agent. In age, sex, underlying disease and serum uric acid level, no significant differences were noted between the two groups. Conclusions : Although joint symptoms are common during antituberculous chemotherapy, their development is difficult to predict. Because some joint symptoms can become very bothersome, the physician should pay close attention to these symptoms.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.8 no.2
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• pp.207-216
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• 1997

This study was conducted to investigate the communicative intent between Reactive Attachment Disorder(RAD) and Developmental Language Disorder(DLD). The subject of this study were 20 27-51 monthold children(10 RAD Children, 10 DLD children) functioning at similar stage of language development. The communicative intent was investigated vertical and horizontal dimension. Rating of vertical communicative intent was based on the assessment scales devised by Wetherby and Prutting(1984). Horizontal dimension was measured by the assessment guidelines of Wetherby and Prizant(1989). All the data were rated by two rators independantly. 1) In communicative intent, vertical development level of DLD children was more sophiscated than that of RAD children. 2) DLD children expressed more horizontal communicative intent than RAD children. The percentage of the three major categories(behavioral regulation, social interaction, and joint attention) of communicative intent in DLD children was lined up social interaction>joint attention>behavioral regulation. On the contrary, RAD children displayed in order of behavioral regulation>social interaction>joint attention. In addition, DLD children showed diversely as compared with RAD children.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.264-267
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• 1996

This paper is aimed to develop a very reliable method for automatic inspection of the solder joints on PCBS. There have been lots of previous works using vision technologies, but they can not be used for inspecting BGA, FCA or other newly used devices. Thus we adopt X-ray technologies for solder joint inspection. We put our attention on reconstructing the 3D shapes of solder joints since it gives us the most detailed information on quality of solder joints. Laminography principle is used to reject the interferences from neighboring parts or leads. To verify the effectiveness of laminography, a simulation study is performed in the case of a solder joints on double sided PCB using.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.105-108
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• 2006

Current ACI and AIJ guidelines only address the importance of the concrete strength and geometry of the joint. There are no significant attention paid to other variables. In addition, the current design code doesn't predict the ductility of the beam-column assemblies. The former researcher proposed the analytical model to predict the shear strength of the joint panel as well as the ductility of the beam-column assemblies in year 2004. In this study, the experiments to investigate shear behavior of reinforced concrete beam-column joints and to verify proposed model were carried out, based on the experimental results. As the formal researcher proposed, the factor K (K=0.5), the ductility of BJ-failure was predicted reasonably when the transverse reinforcement ratio exceeded 0.0186. However, the proposed equation showed a large discrepancies in the ductility estimating when transverse reinforcement ratio was below 0.0186.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.223-224
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• 2022

본 논문에서는 축형 척추관절염으로 발전할 수 있는 천장관절염 환자들을 진단하기 위해 장골의 관심영역을 자동 생성할 수 있는 세그멘테이션 방법을 제안한다. 다양한 MRI 기기로부터 얻은 천장관절염 환자의 영상에서 장골의 GT(Ground Truth)를 생성하였으며, 대장 용종 검출을 위한 세그멘테이션 모델인 PraNet과 지역 특징 간의 표현 능력을 활용할 수 있는 Position Attention Module을 사용하여 유의미한 성능 향상을 보여주었다.

• 한국전산유체공학회:학술대회논문집
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• 2001.05a
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• pp.21-29
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• 2001

For rapid and abrupt control of a missile in supersonic flight, side jet on a missile body is found to be a useful devise as evidenced by recent missile development at several nations. The magnitude of the side jet and the duration of it decide the level of control of such a missile system. In this paper, the aerodynamic characteristics of the side jet devise itself are examined in terms of key parameters such as the side jet nozzle contour, the chamber pressure and temperature. Specifically attention is focused on the effect of the chamber shape between the straight nozzle and the bended nozzle by 90 degrees. The flow properties as well as the thrust level are compared between the two shapes. Particular attention is paid at the way the nozzle is bended at the joint. Effects of the length and the divergence angle of the nozzle on the thrust magnitude are also quantified among the three different side jet nozzles.