• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2005.11a
• /
• pp.244-245
• /
• 2005

This paper presents the performance of BALUN embedded in the LTCC substrate of ZigBee system which is one of the kind of wireless communication. The BALUN is used to make two signal which have 180$^{\circ}$ phase difference and 3dB power from one input signal. Therefore, this is 3-port network circuit. At the center frequency(915MHz), insertion losses were 3.1dB and 3.4dB, respectively. Also, the phase difference was 182$^{\circ}$. Its size is 2.1$\times$3.6mm. The Used materials were dupont9599 LTCC ceramic and daejuo086 Ag.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.31A no.6
• /
• pp.18-25
• /
• 1994

If a 4-port network is terminated by arbitrary impedances, there are great advantageges in composing systems with it. The distributed 3-dB $O^{\circ}$/180$^{\circ}$ hybrid with the impedances asymmetrically terminated is presented. In the band of UHF and VHF. on the basis of it , the new design method of small sized- hybrid using both lumped and distributed elements is also presented and analyzed At the center frequency of 900MHz. 3-dB $O^{\circ}$/180$^{\circ}$hybrid on the RT/Duroid substrate of ${\varepsilon}_{r}$=2.2, h=0.76mm is design and tested. Agreements are obtained between measured and theoretical results and at the same time the occupied area of it is reduced more than 70% compared with only distributed-type circuits.

• Journal of Korea Port Economic Association
• /
• v.36 no.2
• /
• pp.1-18
• /
• 2020

The Internet of things (IoT) has been applied to a variety of industrial uses such as public service sectors, medical industries, automotive industries, and so on. Led by smart cities, this is typical. However, from a logistics perspective, the level of application is insufficient. This study examines the applicability of IoT-related technology in a container terminal, an object of the present invention, to derive an applicable plan. Analytic network process (ANP) analysis reveals the following results for IoT applications in container terminals: operating systems (26.7%), safety/environmental/security systems (26.4%), equipment maintenance systems (25.3%), and facility maintenance systems (21.6 %). The second ANP analysis reveals the following results: Economy (40.2%), productivity (21.1%), service level (19.5%), and utilizing technology level (19.2%). The application or standard of evaluation is important when applying IoT technology to container terminals; however, it is not concentrated in a certain area. It is desirable to build each container system with linkage and efficiency from a macroscopic view.

• Journal of Korea Port Economic Association
• /
• v.31 no.1
• /
• pp.15-36
• /
• 2015

The purpose of this paper is "A Study on the Establishment of Distribution and Logistics System in the unified Korea". The main conclusion of this paper are as follows : North and South Korea shall conjunctionally foster the exchange and cooperation area and operate the joint pilot project to combine distribution and logistics system. To solve the problems of the maritime affairs, Fisheries, and international logistics, the cooperative agreement between North and South Korea will be needed to protect and develop of shipping, aviation and shipbuilding industry. Unification of two Koreas must be prepared as stage by stage ; ${\cdot}$Stage1(preparation period) : initiation of peace area. ${\cdot}$Stage2(development period) : forming the exchange and cooperation area ${\cdot}$Stage3(settlement period) : establishing peace belt on border area. After the unification, two Koreas must plan and undertake the construction of the distribution and logistics infrastructures, establishment of SCM system through Network and the connection to China through railway and road Network.

• Journal of the Korea Society of Computer and Information
• /
• v.10 no.6 s.38
• /
• pp.9-16
• /
• 2005

Recently, since the number of internet users is increasing rapidly and, by using the Public hacking tools, general network users can intrude computer systems easily, the hacking problem is setting more serious. In order to prevent the intrusion. it is needed to detect the sign in advance of intrusion in a Positive Prevention by detecting the various forms of hackers intrusion trials to know the vulnerability of systems. The existing network-based anomaly detection algorithms that cope with port-scanning and the network vulnerability scans have some weakness in intrusion detection. they can not detect slow scans and coordinated scans. therefore, the new concept of algorithm is needed to detect effectively the various. In this Paper, we propose a detection algorithm for session patterns and FCM.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.14 no.3
• /
• pp.1-6
• /
• 2014

Companies almost don't use an integrated control system using expensive network system in multimedia like TV and DID, despite IP-Broadcasting and communication equipment have expanded rapidly. The proposed integrated TCU(terminal control unit) is a control device that supports TV power On/Off check and remote control, power control reservation function, TV channel change, a variety of interface supports of input/output AC power & Lan port, RS-232C and IR using existing IP network after there is installed the Wake-on -Lan in the set-top box. The TCU can control and monitor 24 hours unlike existing low-cost control system RF method. In existing control equipment markets without expandability and low price, the TCU development including 24 hours monitoring and automatic control functions is expected to secure a wide range of companies.

• International journal of advanced smart convergence
• /
• v.6 no.4
• /
• pp.33-40
• /
• 2017

In this paper, complex quadruplet zeros of microwave filter systems are investigated. For the cascaded systems the chain matrices are most conveniently used to derive the voltage transfer function of Laplace transform with cascaded two-port subsystems. The convenient relations of transfer function and chain matrix are used in order to find the transmission zeros. Starting from a ladder network, we introduced a crossed-coupled lumped element, in order to show the improved response of bandpass filter. By solving the transmission zero characteristic equation derived from the cascaded subsystems, we found the zeros of filter system with externally cross-coupled lumped elements. With the cross-coupled elements of capacitors, the numerator polynomial of system transfer function is used to locate the quadruplet zeros in complex plane. When the two pairs of double are on the zeros -axis, with the perturbed values of element, we learned that the transition band of lowpass filter is improved. By solving the characteristic equation of cascaded transfer function, we can obtain the zeros of the cross-coupled filter system, as a result of perturbed values on lumped element.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.20 no.6
• /
• pp.671-676
• /
• 2014

Based on the data of PSC information management system of MOF(Ministry of oceans and fisheries) and APCIS(Asia-Pacific Computerized Information System) of Tokyo-MOU information system, the result of the evaluation on the reality of PSC was done, and base on 2009, it showed a trend of decrease in every DFR(Deficiency Rate) and DTR(Detention Rate). But for vessels built for more than 30 years, flags of convenience vessels, RO-RO ferry and general cargo vessel, small size vessels with gross tonnage less than 1,000 ton showed a high DFR and DTR. Each harbours is classified by the total harbours' average DFR which was 82.5 % and the average DTR was 5.1 %, excluding the Jeju harbour, showing a hugh deviation for classification of each harbour. Classification of each harbour has to be inspected by PSC and it showed a great unbalance of the number of vessels for each territory for inspection. the biggest problem with our country's PSC, where it was pointed out by the PSCO was lack of workers and independent inspection by just one worker. To strength the substantiality of the inspection of our country is to have concentrated inspection on the high risk cautious vessels, forming a human network each classified by four different sectors of the area, recalculating the amount of assignment of inspection classified by each harbour and securing workforce the PSCO improvements are necessary.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.6
• /
• pp.2815-2822
• /
• 2011

Clustering method in wireless sensor networks is the technique that forms the cluster to aggregate the data and transmit them at the same time that they can use the energy efficiently. In this paper, I propose the hierarchical unequal clustering method using cluster group model. This divides the entire network into two layers. The data aggregated from layer 2 consisted of cluster group is sent to layer 1, after re-aggregation the total data is sent to base station. This method decreases whole energy consumption by using cluster group model with multi-hop communication architecture. Hot spot problem can be solved by establishing unequal cluster. I also show that proposed hierarchical unequal clustering method is better than previous clustering method at the point of network energy efficiency.

• Journal of Korea Trade
• /
• v.25 no.6
• /
• pp.78-104
• /
• 2021

Purpose - Semiconductors are a significant export item for Korea that is expected to continue to contribute significantly to the Korean economy in the future. Thus, the semiconductor industry is a critical component in the 4th Industrial Revolution and is expected to continue growing as the non-face-to-face economy expands as a result of the COVID-19 pandemic. In this context, this paper aims to empirically investigate how semiconductors are imported and exported in Korea from a global supply chain perspective by analysing import and export data at the micro-level. Design/methodology - This study conducts a multifaceted analysis of the global supply chain for semiconductors and related equipment in Korea by examining semiconductor imports and exports by semiconductor type, year, target country, mode of transportation, airport/port, and domestic region, using import/export micro-data. The visualisation, flow analysis, and Bayesian Network methodologies were used to compensate for the limitations of each method. Findings - Korea is a major exporter of semiconductor memory and has the world's highest competitiveness but is relatively weak in the field of system semiconductors. The trade deficit in 'semiconductor equipment and parts' is clearly growing. As a result, continued investment in 'system semiconductors' and 'semiconductor equipment and parts' technology development is necessary to boost exports and ensure a stable supply chain. Originality/value - Few papers on semiconductor trade in Korea have been published from the perspective of the global supply chain or value chain. This study contributes to the literature in this area by focusing on import and export data for the global supply chain of the Korean semiconductor industry using a variety of approaches. It is our hope that the insights gained from this study will aid in the advancement of SCM research.