• Journal of the Microelectronics and Packaging Society
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• v.8 no.1
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• pp.1-4
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• 2001

We have fabricated and evaluated a new Si pin photodetector for APF optical link. The fabricated device has the $p^{+}$-guard ring around the metal-semiconductor contact and the web patterned $p^{+}$-shallow diffused region in the light absorbing area. From the measurements of electo-optical characteristics under the bias of -5 V, the junction capacitance of 4 pF and the dark current of 180 pA were obtained. The optical signal current of 1.22 $\mu$A and the responsivity of 0.55 A/W were obtained when the 2.2 $\mu$W optical power with peak wavelength of 670 nm was incident on the device. The fabricated device showed the maximum spectral response in a spectrum of 650-700 nm. It is expected that the fabricated device can be very useful for detecting the optical signal in the application of red light optics.

• Journal of IKEEE
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• v.22 no.2
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• pp.432-439
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• 2018

In this paper, an omnidirectional visible light detector was developed by making the detecting surface of a flexible solar cell in a cylindrical form, which has a uniform receiving pattern in the horizontal plane. This solar cell detector receives simultaneously multiple signal lights incident from different directions and provides electrical power to the ASK demodulator in the receiver. In experiments, time division transmission method was used to receive three signal lights incident from different directions to the solar cell detector. Each signal light was ASK modulated using a carrier of 40 kHz, and the synchronizing pulses required for time division transmission were generated by detecting the 120 Hz AC signal included in the indoor illumination lamp with Cds cells. This receiving structure is useful in constructing an $N{\times}1$ optical link in visible light communication.

• Journal of the Korean Institute of Navigation
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• v.22 no.2
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• pp.13-22
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• 1998

Shipbome Automatic Identification System (AIS) will be an important manne equipment used for identification, surveillance and communication in the 21st century, which is currently being researched in developed countries. A technical scheme of AlS is proposed in this paper. The main component of the AlS is a broadcast transponder, and the core technology is a VHF radio data link with high capacity, named STDMA (Self-organized Time Division Multiple Access). The ships installed the AlS, which will automatically and periodically broadcast their positions and identities in the marine VHF channels, can be displayed on a screen of an ECDIS on board or in VTS centers. The AlS is able to support not only broadcast service but also point-to-point communication service. This paper presents the configuration, operation principle and functionality of the AlS as well as the scenario of STDMA. In addition, the standardization work of AlS in IMO is introduced in this pauer, too.

• Journal of the Korea Society of Computer and Information
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• v.28 no.5
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• pp.9-15
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• 2023

In this paper, we propose a method predicting the speed of each lane from the link speed using a neural network. We took three measures for configuring learning data to increase prediction accuracy. The first one is to expand the spatial range of the data source by including 14 links connected to the beginning and end points of the link. We also increased the time interval from 07:00 to 22:00 and included the data generation time in the feature data. Finally, we marked weekdays and holidays. Results of experiments showed that the speed error was reduced by 21.9% from 6.4 km/h to 5.0 km/h for straight lane, by 12.9% from 8.5 km/h to 7.4 km/h for right turns, and by 5.7% from 8.7 km/h to 8.2 km/h for left-turns. As a secondary result, we confirmed that the prediction accuracy of each lane was high for city roads when the traffic flow was congested. The feature of the proposed method is that it predicts traffic conditions for each lane improving the accuracy of prediction.

• Composites Research
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• v.22 no.3
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• pp.35-43
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• 2009

In this study, for a radiator hose made of carbon black filled EPDM(ethylene-propylene diene monomer) rubber, a measuring method of crosslink density was established to analyze the aging behaviors under thermo-oxidative stresses. At $125^{\circ}C$, the crosslink density of the rubber specimens decreased slightly in the initial stage, but increased with increasing the aging time. Such variation in crosslink density was similar to that of tensile strength. This might be due to the formation of sulphoxide crosslinks as well as to additional crosslinks made by the reaction of unvalcunized sulfurs. A high temperature aging of rubber specimens at $180^{\circ}C$ caused a slight increase in crosslink density while it did a large decrease in tensile strength and elongation. With aging at high temperature, the formation of carbonyl groups in EPDM molecule chain and formation of sulphoxide crosslink, rather than the crosslink density variation itself, had a large influence on such changes in mechanical property.

• Journal of the Korea Computer Graphics Society
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• v.19 no.4
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• pp.13-22
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• 2013

A motion capture system is widely used in movies, computer game, and computer animation industries because it allows for creating realistic human motions efficiently. The inertial motion capture system has several advantages over more popular vision-based systems in terms of the required space and cost. However, it suffers from low accuracy due to the relatively high noise levels of the inertial sensors. In particular, the accelerometer used for measuring gravity direction loses the accuracy when the sensor is moving with non-zero linear acceleration. In this paper, we propose a method to remove the linear acceleration component from the accelerometer data in order to improve the accuracy of measuring gravity direction. In addition, we develop a simple method to calibrate the joint axis of a link to which an inertial sensor belongs as well as the position of a sensor with respect to the link. The calibration enables attaching inertial sensors in an arbitrary position and orientation with respect to a link.

• Journal of IKEEE
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• v.15 no.1
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• pp.15-22
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• 2011

In order to performing the joint operation of Korean army efficiently, informations about surveillance, reconnaissance, and situation awareness need to be possessed jointly. In the first development phase (basis type) of the Korean joint tactical data link system (JTDLS-K), essential tactical information and recognized situation are owned among platforms in common by using existing wireless terminals. In the second development phase (completion type) of the JTDLS-K, a JTDLS which can perform network centric warfare (NCW) will be developed in due consideration of technology development of the basis type and common technology maturity degree. This is a joint battlefield system that can show fighting power simultaneous and polysynthetically through providing command and control messages effectively to each platform, which is participating in the joint and combined operations. In this paper, the development of JTDLS-K with a common data processor based on common link integration processing (CLIP) is described. From the test results of the system presented in this paper, it is demonstrated that quadrature phase shift keying (QPSK) signals can be applied to the system.

• Culinary science and hospitality research
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• v.22 no.4
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• pp.1-23
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• 2016

This research attempts to analyze the relationship among leadership, LMX and organizational achievements for chefs in the Jeju district. The results of the research revealed that the leadership type only affected the servant leadership of LMX. Furthermore, the job satisfaction for leadership and LMX was influenced by organizational commitment. Therefore, to strengthen the relationship of LMX, the leadership type's servant leadership must be the essential link between the relationship of LMX, and LMX serves as the link between leadership and organizational achievement. Ultimately, to augment the employer-employee relationship, the factors of servant leadership must be applied, for example, by taking good care of the workers, persuasion, attentively listening to the workers, sympathy, and suggestion of vision, as well as the mutual link and respect among the employers and employees, all of which were shown to have positive influences on the organizational achievements.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.4 no.3 s.8
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• pp.9-22
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• 2005

Route travel cost in transportation networks consists of actual route travel cost and route perception cost. Since the route perception cost is differently perceived according to each origin and each destination, route search has limitation to reflect the note perception cost due to route enumeration problem. Thus, currently employed advanced traveller information systems (ATIS) have considered only actual route travel cost for providing route information. This study proposes an optimal and a K-route searching algorithm which are able to reflect the route perception cost but encompass route enumeration problem. For this purpose, this research defines the minimum nit of route as a link by adopting the link label technique in route searching, therefore the comparison of two adjacent links which can be finally expanded the comparison of two routes. In order to reflect the characteristics of route perception in real situation, an optimal shortest cost path algorithm that both the forward search from the origin and the backward search from the destination can be simultaneously processed is proposed. The proposed algorithm is applied for finding K number of shortest routes with an entire-path-deletion-type of K shortest route algorithm.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.6
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• pp.13-22
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• 2009

Recently, DSRC technology is used in the various fields such as parking system, BIS, ETC, etc. This paper suggests a traffic information system using this DSRC technology. The traffic information processing based on point detection using existing vehicle detection equipment is the system in which a collection and a service are operated separately while the traffic information system based on the link detection using DSRC is able to collect and provide the traffic information through the communication between RSE and OBU. The speed of a traffic congestion is high on the process converted from a point passing speed to a link average speed because the vehicle detection equipment makes the link traffic information into the point information. When the condition of traffic is deteriorated, traffic speed of the vehicle detection equipment becomes higher than DSRC. Especially, in this system, deflection by data of the traffic speed of the traffic information system is much decreased, and the unexpected condition detection and traffic condition are provided promptly.