• Restorative Dentistry and Endodontics
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• v.24 no.3
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• pp.465-472
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• 1999

The aim of this study was to determine the shear bond properties of four dentin bonding systems to internal cervical dentin, and to investigate the effect of the pretreatment for removing smear layer and position of dentin on shear bond strength of dentin bonding agents. The materials tested in this study were consisted of four commercially available dentin bonding systems[Allbond 2(AB), Clearfil Linerbond 2(CL), Optibond FL(OP), Scotchbond Multi-purpose(SB)], a restorative light-cured composite resin[Z100]J and a chelating agent[RC-prep(RC)]. Fifty-six freshly extracted human molars were used in this study. Dentin specimens were prepared by first cutting the root of the tooth 1mm below the cementoenamel junction with a diamond bur in a high speed handpiece under air-water coolant, and then removing occlusal part at pulp horn level by means of a second parallel section, The root canal areas were exposed by means of cutting the dent in specimens perpendicular to the root axis. Dentin specimens were randomly assigned to two groups(pretreated group, not-pretreated group) based on the pretreatment method of dentin surface. In pretreated group, RC was applied to dentin surface for 1minute and then rinsed with NaOCl. In not-pretreated group, dentin surface was rinsed with saline Each groups were subdevided into four groups according to dentin bonding systems. Four dentin bonding systems and a restorative resin were applied according to the directions of manufacturer. The dentin-resin specimens were embedded in a cold cure acrylic resin, and were cut with a low speed diamond saw to the dimension of $1{\times}1mm$. The cut specimens were divided into three groups according to the position of internal cervical dentin. The shear bond properties of dentin-resin specimens were measured with Universal testing machine (Zwick, 020, Germany) with the cross head speed of 0.5mm/min. From this experiment. the following results were obtained : 1. In case of shear bond strength, there was no significant difference among dentin bonding systems in not-pretreated groups, whereas in pretreated groups, the shear bond strengths of AB and of SB were statistically significantly higher than those of CL and of OP. 2. The shear bond strengths of AB and of SB in pretreated groups were significantly higher than those in not-pretreated groups. 3. The shear bond strengths of radicular layer of OP were higher than those of occlusal layer of OP in not-pretreated groups, and of AB in pretreated groups. The shear bond strengths of radicular layer of AB and of CL in not-pretreated groups were higher than those in pretreated group.

• Journal of the Korean Wood Science and Technology
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• v.37 no.3
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• pp.184-191
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• 2009

In the southern part of the Korean Peninsula including Jeju-island, the production amount of domestic cedar has increased gradually. However, their low qualities, expected to be caused by the low density and frequent knots, have restricted their practical utilization as the high value-added products. In this study, it is aimed to look for the new uses of domestic cedar and to examine the applicability for lamination lumbers of structural glued laminated timber (glulam). Above all, machine stress ratings for individual sawn lumbers confirmed that modulus of elasticity (MOE) of cedar lumber was lower than that of other common softwood species in Korea. On the other hand, cedar lumbers have enough stiffness to manufacture the structural glulam in accordance with Korean Industrial Standard (KS). The bonding strength and durability also met the KS limitation. Nevertheless, from the result of bending tests for cedar glulam, it was shown that the modulus of elasticity (MOE) did not meet the KS limitation. Therefore, it was concluded that additional researches were needed for reinforcing the stiffness of cedar glulam.

• Restorative Dentistry and Endodontics
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• v.10 no.1
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• pp.153-160
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• 1984

The purpose of this study was to observe the tensile and bonding strength of the joined amalgam restoration. Amalgam alloys of fine-cut (F-type), spherical (S-type), and dispersed type (D-type) were selected in this study, and all specimens were divided into three groups according to the condensation methods as follows. Group I : the control group which condense the same kinds of mixed amalgam into the whole part of the mold respectively. Group II : the group which condense a mix of amalgam into one half of the mold, and then condense a new mix of amalgam into the rest half of the mold 15 minutes later. Group III : the group which condense a mixed amalgam into one half of the mold, and then condense a new mix of amalgam into the rest half of the mold 7 days later. All specimens were stored in incubator at $37{\pm}1^{\circ}C$ for seven days with immersing in saline solution before testing. The tensile and bonding strength of them were measured with Instron Universal Testing machine. The results were as follows: 1. In Group I, the order of tensile strength was F-type, S-type, and D-type. 2. In case of bonding of S-type + S-type, the difference of the bonding strength between Group II and III was not significant. (P> 0.05) 3. The bonding strength of F-type + S-type of Group II was marked the highest in value, and the lowest bonding strength was showed in bonded D-type + D-type of Group III. 4. In case of bonding with the different kinds of amalgam alloy in Group II, the specimen bonded to F-type was marked the highest bonding strength, and the specimen bonded with F-type was marked the lowest one. In Group II, the bonding strength of the specimens bonded with the same kinds of amalgam alloy was presented as the same order as that of Group I. 5. In Group III, the specimen connected with D-type marked the lowest bonding strength of all specimens. In Group III, the bonding strength of the specimens connected with the same kinds of amalgam alloy was the order of S-type + S-type, F-type + F-type, and D-type + D-type.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.5
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• pp.162-177
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• 2020

The perception of traffic environment based on various sensors in autonomous driving system has a direct relationship with driving safety. Recently, as the perception model based on deep neural network is used due to the development of machine learning/in-depth neural network technology, a the perception model training and high quality of a training dataset are required. However, there are several realistic difficulties to collect data on all situations that may occur in self-driving. The performance of the perception model may be deteriorated due to the difference between the overseas and domestic traffic environments, and data on bad weather where the sensors can not operate normally can not guarantee the qualitative part. Therefore, it is necessary to build a virtual road environment in the simulator rather than the actual road to collect the traning data. In this paper, a training dataset collection process is suggested by diversifying the weather, illumination, sensor position, type and counts of vehicles in the simulator environment that simulates the domestic road situation according to the domestic situation. In order to achieve better performance, the authors changed the domain of image to be closer to due diligence and diversified. And the performance evaluation was conducted on the test data collected in the actual road environment, and the performance was similar to that of the model learned only by the actual environmental data.

• Journal of the Korean Society for Railway
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• v.20 no.4
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• pp.491-499
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• 2017

Railway turnout systems are one of the most important systems in a railway and abnormal turnout systems can cause serious accidents. To detect an abnormal state of a turnout, turnout clearance detectors are widely used. These devices consider a failure of a turnout clearance detectors to be a failure of the turnout system, that could hinder train operations. Analysis of turnout clearance detector failures is very important to ensure normal train operation. We categorized failures of detectors into four groups to identify failure characteristics of the 140 detectors, which are composed of main line detectors (A), side tracks (B), detectors that are in operation more than 80 times a day (C) and detectors that are in operation fewer than 10 times per day. Failures of detectors have mainly been caused in the control part, in the cables and sensors; failures are classified into four groups (A, B, C and D). We have tried to find failure density distributions for each type of failures, inferring the parameter distributions a priori. Finally, using the Bayesian inference we proposed a maintenance time for control parts through the mean time of the detector, life and the life expectancy.

• The KIPS Transactions:PartD
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• v.14D no.2
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• pp.265-272
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• 2007

In this paper, we implement an automated composition system of web services using hybrid techniques that merge the benefit of BPEL techniques, with the advantage of OWL-S, BPEL techniques have practical capabilities that fulfil the needs of the business environment such as fault handling and transaction management. However, the main shortcoming of these techniques is the static composition approach, where the service selection and flow management are done a priori and manually. In contrast, OWL-S techniques use ontologies to provide a mechanism to describe the web services functionality in machine-understandable form, making it possible to discover, and integrate web services automatically. This allows for the dynamic integration of compatible web services, possibly discovered at run time, into the composition schema. However, the development of these approaches is still in its infancy and has been largely detached from the BPEL composition effort. In this work, we describe the design of the SemanticBPEL architecture that is a hybrid system of BPEL4WS and OWL-S, and propose algorithms for web service search and integration. In particular, the SemanticBPEL has been implemented based on the open source tools. The proposed system is compared with existing BPEL systems by functional analysis. These comparisions show that our system outperforms existing systems.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.11 no.2
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• pp.13-18
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• 2005

The ulnar nerve extends down the arm, across the elbow, and into the hand. It provides sensation to the little and ring fingers and activates many of the small muscles in the hand. The determination of peripheral nerve conduction velocity is an important part of ulnar nerve evaluation. The electrodiagnostic value as neurophysiologic investigative procedure has been known for many years but normal value of digital nerve was not reported in Korea. The purpose of this investigation was to measure the digital nerve conduction velocity of ulnar nerve for obtain clinically useful reference value and compare difference in each fingers and then compare with the other countries. 71 normal Korean volunteers (age, 19-65 years; 142 hands) examined who has no history of peripheral neuropathy, diabetic mellitus, chronic renal failure, endocrine disorders, anti-cancer medicine, anti-tubercle medicine, alcoholism, trauma, radiculopathy. Nicolet Viking II (EMG machine) was use for detected conduction velocity and amplitude of digital nerves in ulnar nerve. Data analysis was performed using SPSS. Descriptive analysis was used for obtain mean and standard deviation and independent t-test was used to compare with ring and little finger. Conduction velocity of the right ring finger was 57.44m/sec and little finger was 55.32msec. The left ring finger was 55.55msec and little finger was 54.11msec. Amplitude of the right ring finger was $30.28{\mu}V$ and little finger was $48.36{\mu}V$. The left ring finger was $30.67{\mu}V$ and little finger was $52.76{\mu}V$. There were significantly difference between ring and little in amplitude (p<.05) but there were no statistically difference between conduction velocity of ring and little finger (p>.05). The amplitude of little finger are greater than ring finger. The present results revealed that electodiagnosis can easily perform in little finger for digital nerve of ulnar nerve study.

• The Journal of the Convergence on Culture Technology
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• v.6 no.1
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• pp.381-388
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• 2020

This paper discusses English Hedges or Hedging Expressions on the basis of their morphosyntactic-pragramatic properties within the perspective of sociolinguistics. The term, 'Hedges' for the past decades since Lakoff(1973), has received little attention from the English grammar circles such as morphosyntax and the generative grammar theories. This paper presents a more comprehensive approach to the identification, distributions, functions, and the morphosyntactic properties of English Hedges. The earlier research on English Hedges in the 70's show that hedges are metalinguistic or mitadiscourse expressions which constitute a means for executing Politeness strategy in pragmatics. Nonetheless, research from the interface of syntactic-pragmatics has been scarce. This article suggests a more complex body of English hedges that have not been extensively discussed in the literature. Additionally, their configurational domain is to be proposed as part of the PolP with [±hedged] above CP⁺ (or CP beyond). The ramifications of the current study are suggested in terms of comparative linguistics, EFL/ESL studies of English for global communication, and pragmatics-sensitive machine translation studies in the forseeable future.

• Korean Journal of Construction Engineering and Management
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• v.1 no.1 s.1
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• pp.87-94
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• 2000

Crack sealing, a routine and necessary part of pavement maintenance, is a dangerous, costly, and labor-intensive operation. Within the North America, about ${\$}200$ million is spent annually on crack sealing, with the Texas Department of Transportation (TxDOT) spending about ${\$}7$ million annually (labor alone accounts for over 50 percent of these costs). Prompted by concerns of safety and cost, the University of Texas at Austin, in cooperation with TxDOT and the Federal Highway Administration (FHWA) has developed a unique computer-guided Automated Road Maintenance Machine (ARMM) for pavement crack sealing. In 1999, successful field tests have been undertaken in 8 States around the U.S. This paper first describes significance of the automated crack sealing and technical advances in automated crack sealers including the ARMM, developed in the U.S. It then discusses the ARMM's field implementation and performance evaluation results, and improvements and modifications suggested through the technology evaluation during the field trials. Current research efforts and future work plans in its further development are also presented in this paper.

• The Journal of Korean Academy of Prosthodontics
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• v.34 no.3
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• pp.620-631
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• 1996

Bonding of resin to cast alloy has traditionally been provided by mechanical retention. But, chemical bonding methods such as silicoating, tin plating, heat treatment, application of 4-META adhesives, have been developed to overcome the problems of the mechanical bonding methods. Silicoating has been used availaby in fixed prosthodontics, but is also reported to be used in removable prosthodontics. The aim of this study is to measure the tensile bond strength between resin and metal, and compare the effect of the type of metal and the grain size of the aluminum oxide on the bond strength, after metal surface roughening, coating of the opaque resin, and curing of heat-curing resin were performed. The test groups were divided into 4 groups according to the cast alloys and the aluminum oxide particles used. Group 1 : Type 4 gold alloy(DM66) blasted with $$50{\mu}m\;Al_{2}O_3$$ Group 2 : Type 4 gold alloy(DM66) blasted with $$250{\mu}m\;Al_{2}O_3$$, Group 3 : Co-Cr alloy(Nobilium) blasted with $$50{\mu}m\;Al_{2}O_3$$ Group 4 : Co-Cr alloy(Nobilium) blasted with $$250{\mu}m\;Al_{2}O_3$$ * 10 test specimens were made on each group. The specimens were thermocycled, and Instron Universal testing machine was used to measure the tensile bond strength of the finished specimens. The results were as follows : 1. Bond strengths showed that the group of gold alloy blasted with $250{\mu}m$ aluminum oxide particle had higher bond strength, and the group of gold alloy blasted with $50{\mu}m$ aluminum oxide particles had lower bond strength than any of the other groups. 2. Gold alloy had significantly higher bond strength when blasted with $250{\mu}m$ aluminum oxide particles than $50{\mu}m$, but. Co-Cr alloy showed no statistically significant difference between the two particle sizes. 3. When blasted with $50{mu}m$ aluminum oxide particles, Co-Cr alloy showed significantly higher bond strength than gold alloy. And, when blasted with $250{\mu}m$ aluminum oxide particles, gold alloy had significantly higher bond strength than Co-Cr alloy. 4. On the examination of the fractured sites, only the group of Co-Cr alloy blasted with $50{\mu}m$ aluminum oxide particles showed a part of residual opaque resin, but all the samples of the other groups fractured between the resin and the metal.