• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.11
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• pp.1139-1145
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• 2014

In shipyard site, a ship is constructed by integrating lots of modules that are made in several sites with different capabilities and specifications. Recently, it needs to make a shipyard to be smart communicating various multimedia information with wired and wireless broadband networks between hierarchical shipyards. In this paper, we propose an additional function of an LTE femtocell local gateway at a remote shipyard, an information exchange method between hierarchical shipyards, and an offload method to separate the general traffic. To reduce traffic of duplicated requests in shipyard, we apply a D2D communication scheme for supporting communication between shipyard equipments without IP service network. Hence, it is expected to increase the productivity of shipyard industry with mobile communications, D2D and broadband Internet technologies.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.5A
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• pp.549-560
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• 2008

In this paper, we propose a new multi-channel MAC protocol to improve the channel efficiency by using two interfaces. Most of previous researches that have considered multi-channel wireless network environments use a common control channel to exchange control signals and they have a bottle neck problem at common control channel as increasing the number of data channels. In the proposed MAC protocol, we separate receiving and transmitting channels so that sending and receiving data and control packets at the same time is possible. It increases the total network throughput. Since there is no common control channel, the network does not suffer from the bottle neck problem. By applying a TDMA scheme, we can avoid packet collisions between data packets and control packets and reduce the possibility of CTS or ACK packet collisions. Simulation results show that the proposed multi-channel MAC protocol improves the total network throughput and channel efficiency compared with the existing method.

• Journal of the Institute of Convergence Signal Processing
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• v.18 no.2
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• pp.43-48
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• 2017

The underwater transients signals contain the characteristics of complexity, time varying, nonlinear, and short duration. So it is very hard to model for these signals with reference patterns. In this paper we separate the whole length of signals into some short duration of constant length with overlapping frame by frame. The 20th LPC(Linear Predictive Coding) coefficients are extracted from the original signals using Durbin algorithm and applied to neural network. The 65% of whole signals were learned and 35% of the signals were tested in the neural network with two hidden layers. The types of the whales for sound classification are Blue whale, Dulsae whale, Gray whale, Humpback whale, Minke whale, and Northern Right whale. Finally, we could obtain more than 83% of classification rate from the test signals.

• The Southeast Asian review
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• v.23 no.3
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• pp.1-48
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• 2013

Taking the cases of Korean garment factories in Binh Duong area, this study aims to explain the phases and causes of the wildcat strikes that have rapidly expanded recently in Vietnam. For the purpose, this study raises several questions as follows. Why the strikes sometimes increase and decrease other times? Why the factory workers prefer a wildcat strike even though it is politically risky, unproductive, and complicated? By the same token, why the foreign management cannot or will not preemptively preclude the wildcat strikes that are usually predictable and the workers are mostly able to accomplish their demands? While answering these questions, this study explores the economic, political, and socio-cultural conditions of the wildcat strikes respectively. Based on the fieldwork in around 30 Korean owned garment factories and the interview with around 100 Vietnamese factory workers in Binh Duong, this study confirms several findings on the phases and causes of the strikes in the area in specific and in Vietnam in general. First, the annual trends of the wildcat strikes reflect the macroeconomic conditions in which the consumer prices and the labor market in Vietnamese economy and business conditions in the world economy are pivotal. Second, however, the influence of macroeconomic conditions on both the management and the workers in the garment factories are differential, depending on the financial situations of the multinational corporations and the workers' capability of reproducing their household economies. Thirdly, the possibility of the wildcat strike in each factory is relatively independent on the financial conditions of a factory and rather associated with the stable political structure and active political processes within the factory that enable the management and the workers to efficiently communicate each other. Lastly, the necessity of establishing political stability in a factory arises from the distinctive social and cultural characteristics of the multinational corporation in which foreign managers and native workers inevitably live in separate and different socio-cultural worlds.

• Convergence Security Journal
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• v.23 no.1
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• pp.125-137
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• 2023

Companies that handle sensitive information, led by public institutions, establish separate networks for work and the Internet and protect important data through strong access control measures to prevent cyber attacks. Therefore, systems that involve the junction where the Intranet(internal LAN for work purposes only) and the Internet network are connected require the establishment of a safe security environment through both administrative and technical measures. Mobile Device Management(MDM) solutions to control mobile devices used by institutions are one such example. As this system operates by handling sensitive information such as mobile device information and user information on the Internet network, stringent security measures are required during operation. In this study, a model was proposed to manage sensitive information data processing in systems that must operate on the Internet network by managing it on the internal work network, and the function design and implementation were centered on an MDM solution based on a network interconnection solution.

• Convergence Security Journal
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• v.22 no.4
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• pp.169-178
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• 2022

In general, organizations operating multi-domain networks find it difficult to represent and manage multiple domain net works on a single screen space. Instead, most of them are managed with multiple screens visualizing network topology by domain or partitioning one screen area into multiple domains. We propose an efficient method to visualize the topology using only minimal connection information between domain-agnostic nodes in this work. This method visualizes the topology by utilizing centrality indices representing the influence of nodes in the network. Furthermore, the method dynamically segments the entire node's display area using virtual Root nodes to auto-separate domains and weights of child nodes and placing nodes in 3D space. Thus, although it is a straightforward method, the multi-domain network topology can be visualized with only minimal connection information between nodes.

• Korean Chemical Engineering Research
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• v.62 no.2
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• pp.181-190
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• 2024

Here, we develop a centrifugal microfluidic reactor with simple, fast, and high-throughput manner for the generation of magnetic Janus micro-adsorbents (MAs). By using the multi-micronozzle consisting of two separate aligned needles and centrifugal tubes, we have synthesized highly monodispersed Prussian blue- and magnetic nanoparticle-laden micro-adsorbents (PB-MNP-MAs). The enhanced cesium (Cs⁺) adsorption was demonstrated by conducting the adsorption isotherm and kinetics experiment which can be contributed to the porous nature of the Ca-alginate networks with a high surface area of embedded PB nanoparticles, resulting to perform rapid adsorption activity within 10 min. After Cs⁺ adsorption process, the as-synthesized PB-MNP-MAs were successfully harvested by introducing the external magnetic fields. Therefore, we believe that our findings can be provided new direction towards the development of advanced functional adsorbents in biological and environmental fields.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.4
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• pp.31-40
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• 2016

In vehicular ad-hoc networks (VANETs), vehicles sense information on emergency incidents (e.g., accidents, unexpected road conditions, etc.) and propagate this information to following vehicles and a server to share the information. However, this process of emergency message propagation is based on multiple broadcast messages and can lead to broadcast storms. To address this issue, in this work, we use a novel approach to detect the vehicles that are farthest away but within communication range of the transmitting vehicle. Specifically, we discuss a signal-to-noise ratio (SNR)-based linear back-off (SLB) scheme where vehicles implicitly detect their relative locations to the transmitter with respect to the SNR of the received packets. Once the relative locations are detected, nodes that are farther away will set a relatively shorter back-off to prioritize its forwarding process so that other vehicles can suppress their transmissions based on packet overhearing. We evaluate SLB using a realistic simulation environment which consists of a NS-3 VANET simulation environment, a software-based WiFi-IP gateway, and an ITS server operating on a separate machine. Comparisons with other broadcasting-based schemes indicate that SLB successfully propagates emergency messages with latencies and hop counts that is close to the experimental optimal while reducing the number of transmissions by as much as 1/20.

• Journal of Plant Biotechnology
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• v.2 no.2
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• pp.61-71
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• 2000

By screening a cDNA library of auxin-treated mung bean (Vigna radiata L.) hypocotyls, we have isolated two full-length cDNA clones, pVR-ACS6 and pVR-ACS7, for 1-aminocyclopropane-1-carboxylate (ACC) synthase, the rate-limiting enzyme in the ethylene biosynthetic pathway. While PVR-ACS6 corresponds to the previously identified PCR fragment pMBA1, pVR-ACS7 is a new cDNA clone. A comparison of deduced amino acid sequences among auxin-induced ACC synthases reveal that these enzymes share a high degree of homology (65-75%) to VR-ACS6 and VR-ACS7 polypeptides, but only about 50% to VR-ACS1 polypeptide. ACS6 and ACS7 are specifically induced by auxin, while ACS1 is induced by cycloheximide, and to lesser extent by excision and auxin treatment. Results from nuclear run-on transcription assay and RNA gel blot studies revealed that all three genes were transcriptionally active displaying unique patterns of induction by IAA and various hormones in etiolated hypocotyls. Particularly, 24-epibrassinolide (BR), an active brassinosteroid, specifically enhanced the expression of VR-ACS7 by distinct temporal induction mechanism compared to that of IAA. In addition, BR synergistically increased the IAA-induced VR-ACS6 and VR-ACS7 transcript levels, while it effectively abolished both the IAA- and kinetin-induced accumulation of VR-ACS1 mRNA. In light-grown plants, VR-ACS1 was induced by IAA in roots, whereas W-ACS6 in epicotyls. IAA- and BR-treatments were not able to increase the VR-ACS7 transcript in the light-grown tissues. These results indicate that the expression of ACC synthase multigene family is regulated by complex hormonal and developmental networks in a gene- and tissue-specific manner in mung bean plants. The VR-ACS7 gene was isolated, and chimeric fusion between the 2.4 kb 5'-upstream region and the $\beta$-glucuronidase (GUS) reporter gene was constructed and introduced into Nicotiana tobacum. Analysis of transgenic tobacco plants revealed the VR-ACS7 promoter-driven GUS activity at a highly localized region of the hypocotyl-root junction of control seedlings, while a marked induction of GUS activity was detected only in the hypocotyl region of the IAA-treated transgenic seedlings where rapid cell elongation occurs. Although there was a modest synergistic effect of BR on the IAA-induced GUS activity, BR alone failed to increase the GUS activity, suggesting that induction of VR-ACS7 occurs via separate signaling pathways in response to IAA and BR.

• Journal of Satellite, Information and Communications
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• v.9 no.1
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• pp.51-56
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• 2014

High-availability seamless redundancy (HSR) is a protocol for fault-tolerant Ethernet (FTE) networks. It provides two frame copies and each copy is forwarded on a separate physical path, which provides zero fail-over time. Therefore, the HSR is becoming a potential candidate for various real-time FTE applications. However, the generation and circulation of unnecessary frames due to the duplication of every sending frame is inherent drawback of HSR. Such drawback degrades the performance of the network and may deplete its resources. In this paper, we present a new algorithm called port locking (PL) based on the media access control (MAC) address to solve the abovementioned problem in popular connected-rings network. Our approach makes the network gradually learn the locations of the source and the destination nodes without relying on network control frames. It then prunes all the rings that do not contain the destination node by locking corresponding rings' entrance ports. With the PL algorithm, the traffic can be significantly reduced and therefore the network performance will be greatly enhanced specially in a large scale connected-rings network. Analytical results are provided to validate the PL algorithm.