• The Journal of Korean Society of Virology
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• v.30 no.1
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• pp.83-99
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• 2000

A defective HIV-1 helper virus DNA, pHyPC, was assembled by deleting the RNA packaging signal, env, nef and the 3'LTR sequences. HIV-1 like virus particles that carry the HIV-1 receptor, CD4 were generated by co expression of pHyPC and plasmid DNAs encoding different chimeric CD4 proteins. The CD4 particles, sharing the CD4 ectodomain, precisely fused to different membrane anchors. CD4(+) particles specifically bound to HIV-1 Env expressing cells, but any signs of infection into these cells were not detected. Binding was only partially blocked by either polyclonal anti-CD4 antibodies or by high concentrations of soluble CD4. Surprisingly, CD4(+) particles also adsorbed to HeLa, CHO, NIH3T3 and COS-7 cells in the absence of HIV-1 Env expression. Adsorption was comparable in strength and speed to the highly specific CD4-Env interaction. CD4(-) particles exhibited only background levels of binding. Cell binding was CD4. dependent, but it was independent of the cell type from which the CD4(+) particles originated. Interestingly, CD4-dependent/Env-independent binding was only found when CD4 was present on virus particles. This suggests that the micro-environment of CD4 on virus particles uniquely expose this new cell binding activity. Its high affinity could explain in part why infection of Env(+) cells by CD4(+) particles was not detected. Further experiments will be required to evaluate whether this strong membrane interaction could represent one step in the multiple-step viral entry process.

• Journal of the Korea Society of Computer and Information
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• v.13 no.7
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• pp.181-188
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• 2008

Nowadays, WiMAX which provides internet service with a middle and low speed serves more function and is wider than Wi-Fi. While they solve the security risks as subscribers do handover by subscriber's re-certification procedure as the Network range is getting wider, there are more security problems making the problems of electric-power consumption and delay. This paper suggests a handover mechanism which simplify the subscriber's re-certification procedure and prevents a security problem as doing handover for solving the problem of delay and the rate of processing. The mechanism can cooperate with PKI structure to increase flexibility and security and minimize network re-entry procedure or re-certification procedure by providing continual service. As a result. the mechanism's throughput as the number of subscribers is lower than IEEE 802.16e and the mechanism proves that it is secure from the attack of man-in-the-middle and reply as doing handover.

• Journal of Korea Technology Innovation Society
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• v.12 no.1
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• pp.237-264
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• 2009

Many Korean companies wanted to improve technological competitiveness and business performance radically through technology leadership initiatives. In-depth case studies about successful Korean technological innovation in the technology generation stage have potential to minimize Korea and developing country firms' trial and error when they are pursuing new technological innovation in the technology generation stage. There are few studies about developing country firms' technological innovations in the technology generation stage and especially process innovation studies are far less performed compared to product innovation studies. This is an exploratory study of POSCO's FINEX process technology innovation in the technology generation stage. These are my findings from this study. Firstly, leadership innovation in the technology generation stage is not a continuous development of catch-up innovation in the technology internalization stage and only top managements can initiate highly risky leadership innovation. Secondly, developing country firms which lacked in technological capability overcomes difficulties in the early stage through complementary technological collaboration with R&D first-movers. Thirdly, this company become a technology leader in spite of late entry in technology development race with developed country firms through rapid scale-ups.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.9
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• pp.1244-1253
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• 2021

In this paper, we propose a method for predicting in advance whether pedestrians will enter the hazardous area after the current time using the pedestrian trajectory prediction method and an efficient simplification method of the trajectory prediction network. In addition, we propose a method to apply KD(Knowledge Distillation) to a small network for real-time operation in an embedded environment. Using the correlation between predicted future paths and hazard zones, we determined whether to enter or not, and applied efficient KD when learning small networks to minimize performance degradation. Experimentally, it was confirmed that the model applied with the simplification method proposed improved the speed by 37.49% compared to the existing model, but led to a slight decrease in accuracy. As a result of learning a small network with an initial accuracy of 91.43% using KD, It was confirmed that it has improved accuracy of 94.76%.

• The Journal of the Korea Contents Association
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• v.21 no.7
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• pp.386-403
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• 2021

Preannouncing a new product to its target audiences has been more and more prevalent in a wealth of industries, particularly industries that attach great importance to the speed of entry. Grounded in market signaling theory, the current research advances a theoretical model that takes full cognizance of the relation between preannounced information about an upcoming product and individual customers' behavioral intentions as well as significant moderating effects of prior product knowledge and new product innovativeness. In response, a web-based survey is conducted for data collection and the structural equation model is utilized for data analysis. Results of this study demonstrate that preannounced new product information attributes (i.e., quantity, clarity) may positively influence consumers' attitudes, in turn, lead to a favorable purchase intention. Moreover, the moderating effects of product knowledge and product innovativeness are also confirmed. Specifically, product knowledge moderates the quantity-attitude relation positively and moderates the clarity-attitude relation negatively, whereas product innovativeness does opposite. Both implications and limitations are also described.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.142-144
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• 2016

Recent promising technologies of the manufacturing sector interest, and the interest in 3D printing that is expected to cause a huge ripple effect rapidly, and various types of products advertised in accordance with the falling price of 3D printers is spreading. However, the personal 3D printers that are currently being advertised is used for Injection output of the simple type that does not require a high processing precision in accordance with the limitation of technical performance, and consumer satisfaction is very low. In this paper, we propose a 3D printer, 3D precision to overcome existing limitations in the way the printer's high SLA 3D printer that combines injection method and the LSU (Laser Scanning Unit) in the office laser printer polygon mirror scanning method. 3D printers which are proposed to improve the accuracy and manufacturing speed is expected to replace the existing entry-level 3D printer.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.3
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• pp.86-99
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• 2021

This research proposes the Accident Prevention System to prevent collision accident that can occur due to blind spots such as crossway or school zone using V2I communication. Vision sensor and LiDAR sensor located in the infrastructure of crossway somewhere like that recognize objects and warn vehicles at risk of accidents to prevent accidents in advance. Using deep learning-based YOLOv4 to recognize the object entering the intersection and using the Manhattan Distance value with LiDAR sensors to calculate the expected collision time and the weight of braking distance and secure safe distance. V2I communication used ROS (Robot Operating System) communication to prevent accidents in advance by conveying various information to the vehicle, including class, distance, and speed of entry objects, in addition to collision warning.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.6
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• pp.1063-1068
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• 2022

The modern society has become entry into the information age after the spread of Internet. In the information age, internet was developed from the wired access to the wireless Internet access. When a surge in demand for wireless Internet access, performance and speed of 2.4 and 5GHz band for Wi-Fi which leads to saturation of the communication was significantly fall. Accordingly, the communication of the 6GHz band for Wi-Fi 6E came to be interested. In this paper, we studied the design and fabrication of microstrip patch antenna to be used in wireless communication systems operating at around 6GHz band. To obtain antenna parameters such as patch size, inter patch space, antenna was simulated by HFSS(High Frequency Structure Simulator). From these parameters, slot microstrip patch antenna is fabricated using FR-4 of dielectric constant 4.4. The characteristics of fabricated patch type microstrip antenna were analyzed by network analyzer.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.6
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• pp.1081-1086
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• 2023

The rapid growth and increasing complexity of modern networks have highlighted the limitations of traditional network architectures. The emergence of SDN (Software-Defined Network) in response to these challenges has changed the existing network environment. The SDN separates the control unit and the data unit, and adjusts the network operation using a centralized controller. However, this structure has also recently caused a huge amount of traffic due to the rapid spread of numerous Internet of Things (IoT) devices, which has not only slowed the transmission speed of the network but also made it difficult to ensure quality of service (QoS). Therefore, this paper proposes a method of load distribution by switching the IP and any server (processor) from the existing data processing scheduling technique, RR (Round-Robin), to mapping when a large amount of data flows in from a specific IP, that is, server overload and data loss.

• Journal of the Korean Professional Engineers Association
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• v.28 no.4
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• pp.54-75
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• 1995

This synthesis has been prepared from a review of literature on Truck Escape Ramps technology and a survey of current practice by state department of transportation. Their locations have been determined usually from a combination of accident experience and en-gineering judgement, but new tools are emerging that can identify needs and sites without waiting for catastrophic accidents to happen. The Grade Severity Rating Systems holds promise in this regard. Design Procedures for truck excape ramps continue to evolve. Gravel arrester beds are clearly the preferred choice across the country Rounded aggregate, uniformly graded in the approximate size range of 13 to 18mm. Tech-nical publications typically have dassified TER types as paved gravity, sandpile, and ar-rester bed ramps. The design speed for vehicle entry into the ramp in critical to the deter-mination of ramp length. An escape ramp should be designed for a minimum entry speed of 130km/hr, a 145km/hr design being preferred. The ramps should be straight and their angle to the roadway align-ment should be as possible. The grade of truck escape ramps show the adjustment of ramp design to local topography, such as the tradeoff of ramp length against earthwork requirements. A width of 9 to 12m would more safety acommodate two or more outof con-trol vehicles. Reguarding comments on the most effective material, most respondents cited their own specification or referred to single graded, rounded pea gravel. The consensus essentially Is that single graded, well -rounded gravel is the most desirable material for use in arrester beds. The arrester beds should be constructed with a minimum aggregate depth of 30cm. Successful ramps have used depths between 30 and 90cm.