• Journal of Korea Multimedia Society
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• v.11 no.2
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• pp.214-227
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• 2008

As cellular network technologies continue to evolve, various network standards coexist in most CDMA-based cellular networks. This means that mobile device users access mobile services over different network bandwidths according to the users' positions or the mobile devices' network access capabilities. Such differences of network bandwidths cause big differences in service response times. To address this problem, we present a framework called CANS (Context-Aware framework for mobile Navigation Services), which takes into account the user's network profile to adapt the contents for CDRG(Centrally Determined Route Guidance) navigation services for cellular phones. To the best of the authors' knowledge, CANS is the first context-aware framework to make mobile navigation services more feasible. The experimental results under commercial CDMA network show that CANS is able to provide similar service response times regardless of type of wireless network to which users connect by adapting the contents to network bandwidths.

• The Journal of the Korea Contents Association
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• v.20 no.4
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• pp.264-272
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• 2020

This study focused on the reality that the necessity to professionalize women marriage immigrants is increasing. The purpose of this study is to analyze the determinants of rural female marriage immigrants' entry into the specialized field. The factors are categorized into social and institutional factors. Based on the labor market segmentation theory, which finds the imbalance of the labor market in terms of institutional and structural factors, factors affecting rural female marriage immigrants entering managerial or professional occupations were set as social relation factors, cultural adaptation factors, and policy support experience factors. As a result of analysis, they are all found to have a statistically significant effect on rural female marriage immigrants entering managerial or professional occupations. The policy implications are that for rural immigrant women to grow into professionals, social relations and cultural learning capabilities, including language skills, need to be strengthened, as well as continued governmental support.

• Journal of Microbiology and Biotechnology
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• v.28 no.9
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• pp.1517-1526
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• 2018

Investigating bacterial diversity and its metabolic capabilities is crucial for interpreting the ecological patterns in a desert environment and assessing the presence of exploitable microbial resources. In this study, we evaluated the spatial heterogeneity of physicochemical parameters, soil bacterial diversity and metabolic adaptation at meter scale. Soil samples were collected from two quadrats of a desert (Thar Desert, India) with a hot, arid climate, very little rainfall and extreme temperatures. Analysis of physico-chemical parameters and subsequent variance analysis (p-values < 0.05) revealed that sulfate, potassium and magnesium ions were the most variable between the quadrats. Microbial diversity of the two quadrats was studied using Illumina bar-coded sequencing by targeting V3-V4 regions of 16S rDNA. As for the results, 702504 high-quality sequence reads, assigned to 173 operational taxonomic units (OTUs) at species level, were examined. The most abundant phyla in both quadrats were Actinobacteria (38.72%), Proteobacteria (32.94%), and Acidobacteria (9.24%). At genus level, Gaiella represented highest prevalence, followed by Streptomyces, Solirubrobacter, Aciditerrimonas, Geminicoccus, Geodermatophilus, Microvirga, and Rubrobacter. Between the quadrats, significant difference (p-values < 0.05) was found in the abundance of Aciditerrimonas, Geodermatophilus, Geminicoccus, Ilumatobacter, Marmoricola, Nakamurella, and Solirubrobacter. Metabolic functional mapping revealed diverse biological activities, and was significantly correlated with physicochemical parameters. The results revealed spatial variation of ions, microbial abundance and functional attributes in the studied quadrats, and patchy nature in local scale. Interestingly, abundance of the biotechnologically important phylum Actinobacteria, with large proposition of unclassified species in the desert, suggested that this arid environment is a promising site for bioprospection.

• Journal of Navigation and Port Research
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• v.40 no.4
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• pp.189-196
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• 2016

We propose a virtual sailor training platform which supports emergency drills for ship's fire in virtual environment. Proposed platform not only enhances training efficiency by providing immersiveness, but also enables a consolidated virtual training due to the network-based multiplayer capabilities. Based on the offline fire simulation results using FDS and CFAST the platform visualizes a realistic fire spread in real-time. The training platform on the basis of the fire training material of the maritime safety education institute induces equipment proficiency and environment adaptation throughout immersive virtual environment in addition to procedure proficiency as well. In the implementation we showed that the equipment and environment controls and telepresence improve the training proficiency and enable collaborative virtual training that participates multiple trainees and induces cooperation for a common goal. Implementation of the platform demonstrated the skill mastery capability of the drill such as efficient fire apparatus controls and passenger controls.

• The Journal of Information Systems
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• v.14 no.2
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• pp.215-236
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• 2005

The purpose of this paper is to examine the differences in the critical success factors for ERP adoption suggested by the system managers and the ERP consultants. The survey results indicated the following findings. First, there was no significant difference in the relative importance of the critical success factors between the system managers and the ERP consultants. Both groups agree that 'top manager's concern and support' is the most critical factor and that 'user involvement' is the second. However, the system managers tend to think 'training and education of end users' and 'cooperations among the project participants' more important than the consultants do. Second, both groups agree that the most important ERP contribution should be 'improvements in the business processes.' They also agree that the least important aspect is 'ERP's contribution to the individual's productivity.' In overall, the ordered lists of ERP evaluation criteria according to their importances were of no significant difference between the groups. Third the two groups showed differences when they were asked to evaluate the importance of the critical success factors for each of the ERP evaluation criterion. In general, the system managers tend to put more emphasis on 'training and education of end users' and 'adaptation of end users to the changed processes,' whereas the consultants tend to emphasize more on 'top managers' interest and supports' and 'project manager's capabilities and performance.' The differences in the critical success factors presented by the two groups indicated that more efforts need to be devoted to understanding other participant's interests and concerns in an ERP project team. Better coordinations based on the mutual understandings could improve the chance of achieving a success in adopting ERP packages.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.1 no.1
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• pp.21-33
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• 1997

This dissertation deals with the design and VLSI implementation of the MTP(Multimedia Transport Protocol) protocol for the high speed networks. High throughput, functional diversity and flexible adaptation are key requirements for the future transport protocol. However it is very difficult to satisfy all these requirements simultaneously. Fortunately, the future networks will be very reliable. It means that the future transport protocol will usually perform some fixed functions without the protocol state information. According to this concept, we proposed and designed the MTP protocol that is consisted of Information Plane and Control Plane. Information Plane performs some fixed functions that are independent of the protocol state information as far as no error. However Control Plane manages the protocol state information and controls the operation of Information Plane. Our MTP protocol was finally implemented as an FPGA chip using the VHDL. We built a testbed for verification of the implemented protocol, and it was shown that the MTP protocol worked correctly and made a throughput of about 800 Mbps. Our future works include the addition of multiplexing and multicasting capabilities to our protocol for multimedia applications.

• The KIPS Transactions:PartD
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• v.9D no.2
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• pp.289-296
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• 2002

The web, which is most actively used in the internet environment, is changing educational system. Students usually prefer the interactive and multimedia learning aids based on web applications and web media to static web pages. The former is known to enhance the effectiveness of learning. This paper proposes a study system which involves effective adaptation to the various changing factors of learners' progress and the corresponding automated evaluation system. Conventional evaluation utilizes normalized method, where the learning objectives generally set by the instructors or educational operators/administrators are usually pursued rather than the interest of the individual learners, which is not ideal for the computer-based learning. Web-based project-oriented learning system provokes the mutual participations among the users, operators, and administrators in understanding the jobs to be performed and the effort to enhance the progressive developments of knowledge and application capabilities. In this Paper, an automated evaluation system is implemented, where the instructors and web-operators/administrators work as hosts for education. The learners take advantage of user-oriented comparative learning and pattern design. The design and implementation of the project-oriented evaluation methods performed in the internet/intranet environments are discussed.

• Journal of Korea Foundry Society
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• v.37 no.3
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• pp.71-77
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• 2017

Casting defects produced during the casting process seriously affect the mechanical properties of the resulting products, reduce the performance capabilities of the product, and also result in economic losses. Therefore, this paper mainly investigates the causes of defects and methods by which to reduce these defects stemming from molten metal flows in a runner system of the type widely used in the sand mold casting process. The flow characteristics of a molten alloy are difficult to observe during the actual casting process. For this reason, a water model was used to observe the flow in the casting process, and the flow in each case was recorded using high-speed cameras as part of the experimental process of this study. Several repetitive experiments were performed to improve the accuracy of the experimental results. The traditional casting system was modified according to the design rules proposed by Campbell, and the system was termed flow-adaptive gating system with a water model. Comparing the flow characteristics of traditional and adaptive gating systems with a water model shows that the bubbles in the water in the latter case are reduced more significantly than in the former case. A ceramic filter system was adapted to the flow-adaptive gating system to minimize the instability of the flow during filling, which occurs as the fluid velocity in the runner increases. In additional, the flow behavior with and without the filter system were compared. The water model system in this work was shown to be able to verify that the adaptation of the filter system brings improvements by stabilizing the flow and reducing the amount of bubbles in the runner system. Moreover, using the flow-adaptive runner system with the filter system leads to considerably stable flows in the runner system.

• Journal of Korean Neurosurgical Society
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• v.65 no.4
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• pp.572-581
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• 2022

Objective : Compared to microscopes, exoscopes have advantages in field-depth, ergonomics, and educational value. Exoscopes are especially well-poised for adaptation into fluorescence-guided surgery (FGS) due to their excitation source, light path, and image processing capabilities. We evaluated the feasibility of near-infrared FGS using a 3-dimensional (3D), 4 K exoscope with near-infrared fluorescence imaging capability. We then compared it to the most sensitive, commercially-available near-infrared exoscope system (3D and 960 p). In-vitro and intraoperative comparisons were performed. Methods : Serial dilutions of indocyanine-green (1-2000 ㎍/mL) were imaged with the 3D, 4 K Olympus Orbeye (system 1) and the 3D, 960 p VisionSense Iridium (system 2). Near-infrared sensitivity was calculated using signal-to-background ratios (SBRs). In addition, three patients with brain tumors were administered indocyanine-green and imaged with system 1, with two also imaged with system 2 for comparison. Results : Systems 1 and 2 detected near-infrared fluorescence from indocyanine green concentrations of >250 ㎍/L and >31.3 ㎍/L, respectively. Intraoperatively, system 1 visualized strong near-infrared fluorescence from two, strongly gadolinium-enhancing meningiomas (SBR=2.4, 1.7). The high-resolution, bright images were sufficient for the surgeon to appreciate the underlying anatomy in the near-infrared mode. However, system 1 was not able to visualize fluorescence from a weakly-enhancing intraparenchymal metastasis. In contrast, system 2 successfully visualized both the meningioma and the metastasis but lacked high resolution stereopsis. Conclusion : Three-dimensional exoscope systems provide an alternative visualization platform for both standard microsurgery and near-infrared fluorescent guided surgery. However, when tumor fluorescence is weak (i.e., low fluorophore uptake, deep tumors), highly sensitive near-infrared visualization systems may be required.

• International Journal of Computer Science & Network Security
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• v.22 no.10
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• pp.191-200
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• 2022

Constrained Application Protocol (CoAP) is a standardized protocol by the Internet Engineering Task Force (IETF) for the Internet of things (IoT). IoT devices have limited computation power, memory, and connectivity capabilities. One of the significant problems in IoT networks is congestion control. The CoAP standard has an exponential backoff congestion control mechanism, which may not be adequate for all IoT applications. Each IoT application would have different characteristics, requiring a novel algorithm to handle congestion in the IoT network. Unnecessary retransmissions, and packet collisions, caused due to lossy links and higher packet error rates, lead to congestion in the IoT network. This paper presents an adaptive congestion control protocol for CoAP, Adaptive Congestion Control with a Backoff algorithm (ACCB). AACB is an extension to our earlier protocol AdCoCoA. The proposed algorithm estimates RTT, RTTVAR, and RTO using dynamic factors instead of fixed values. Also, the backoff mechanism has dynamic factors to estimate the RTO value on retransmissions. This dynamic adaptation helps to improve CoAP performance and reduce retransmissions. The results show ACCB has significantly higher goodput (49.5%, 436.5%, 312.7%), packet delivery ratio (10.1%, 56%, 23.3%), and transmission rate (37.7%, 265%, 175.3%); compare to CoAP, CoCoA+ and AdCoCoA respectively in linear scenario. The results show ACCB has significantly higher goodput (60.5%, 482%,202.1%), packet delivery ratio (7.6%, 60.6%, 26%), and transmission rate (40.9%, 284%, 146.45%); compare to CoAP, CoCoA+ and AdCoCoA respectively in random walk scenario. ACCB has similar retransmission index compare to CoAp, CoCoA+ and AdCoCoA respectively in both the scenarios.