• Journal of KIISE:Information Networking
• /
• v.33 no.6
• /
• pp.420-427
• /
• 2006

An RFID system is an important technology that could replace the traditional bar code system changing the paradigm of manufacturing, distribution, and service industry. An RFID reader can recognize several hundred tags in one second. Tag identification is done by tags' random transmission of their IDs in a frame which is assigned by the reader at each round. To minimize tag identification time, optimal frame size should be selected according to the number of tags. This paper presents new query optimization methods in RFID systems. Query optimization consists of tag number estimation problem and frame length determination problem. We propose a simple yet efficient tag estimation method and calculate optimal frame lengths that minimize overall query time. We conducted rigorous performance studies. Performance results show that the new tag number estimation technique is more accurate than previous methods. We also observe that a simple greedy method is as efficient as the optimal method in minimizing the query time.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.41 no.5
• /
• pp.485-492
• /
• 2021

This study focused on safety aspects surrounding energy consumption in the seawater desalination process in the Daesan Industrial Complex located on the West Sea coast. The safety index for energy consumption was evaluated under different salinities and temperatures of the incoming seawater. Temperature and salinity input data for the 1997-2018 period were obtained from the Marine Environment Information System, and the power required for reverse osmosis (RO) was applied to the program as per the data provided by the RO membrane manufacturer (Q-Plus v3.0). Notably, reasonable energy consumption guidelines were proposed during the design of the desalination facilities; in this regard, the desalination process required approximately 2.10-2.90 kWh/m³ electrical power. Moreover, the energy safety based on 95 % was estimated to be 2.80 kWh/m³ when the desalination facility was operated.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.19 no.1
• /
• pp.171-178
• /
• 2019

Korea's shipbuilding industry is in a critical condition due to changes in the domestic and international environment. To overcome this crisis, preemptive development of products and technologies through prediction of new demand for ships is necessary. The goal of this research is to develop an artificial intelligence algorithm based on ship big data in order to predict new demand for ships. We intend to develop a big data analytics platform specialized in predicting ship demand and to utilize the forecast results of new ship demand through data analysis for planning/development of new products. By doing so, the development of sustainable new business models for equipment and equipment manufacturers will create new growth engines for shipyard and shipbuilders. Furthermore, it is expected that shipbuilders will be able to create business cases based on measurable performance, plan market-oriented products and services, and continuously achieve innovation that has high market destructive power.

• Journal of Internet of Things and Convergence
• /
• v.6 no.4
• /
• pp.59-64
• /
• 2020

Recently, many difficulties have been faced in all parts of the world due to the impact of COVID-19. Personally, household income is decreasing sharply as many jobs disappear, and economically, many SMEs are increasingly going bankrupt. It is known that this phenomenon is highly likely to continue for the time being. In such a situation, the smart factory support project provides opportunities for difficult SMEs to improve productivity and change the corporate structure. In this study, the current status of smart factory promotion was examined, and problems occurring in the process of promoting smart factory support projects were identified. The improvement plans were derived so that more efficient projects could be promoted in the future.

• Applied Chemistry for Engineering
• /
• v.32 no.1
• /
• pp.91-96
• /
• 2021

This study was conducted to improve the operating conditions of an adsorption tower filled with potassium impregnated activated carbon for high hydrogen sulfide capture capacity. Heat treatment modified the surface properties of activated carbon, and ultimately determined its adsorption capacity. The activated carbon doped with potassium showed 57 times more adsorption at room temperature than that of using the raw adsorbent. It is believed that uniform pore formation and strong bonding of the potassium on the surface of carbon contributed to the chemical and physical absorption of hydrogen sulfide. The SEM analysis on the surface structure of various commercial carbons showed that the modification of surface properties through the heat treatment generated the destruction of pore structures resulted in the decrease of the absorption performance. The pressure drop across the activated carbon bed was closely related with the grain size and shape. The optimum size of irregularly shaped activated carbon granules was 2~4 mesh indicating economical feasibility.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.27 no.3
• /
• pp.159-167
• /
• 2021

The need for biodegradable plastic continues to increase, improvement of physical properties is necessary for actual use in the market. In this study, composite film was produced by adding peroxide additives to bioplastic according to concentration to investigate changes in the melt index, elongation, morphology, and TGA of the composite film. The addition of peroxide compatibilizer showed superior elongation of film and TGA compared to those of control. The added amount of compatibilizer affected the extrusion process, and it was revealed that adding an appropriate amount of peroxidizer is important. Analysis of the composite film's morphology revealed a heterogeneous dispersion sequence due to different rates of crystallization depending on the resin, and surface physical properties were best in the group added with 4% peroxide. The results above showed that the test group added with 4% peroxide compatibilizer was superior in the production of composite biodegradable film.

• Knowledge Management Research
• /
• v.23 no.2
• /
• pp.37-60
• /
• 2022

The growth of virtual reality games and the popularization of blockchain technology are bringing significant changes to the formation of the metaverse industry ecosystem. Especially, after Meta acquired Oculus, a VR device and application company, the growth of VR-based metaverse services is accelerating. In this study, the concept that supports leisure activities in the metaverse environment is explored realting to game-like features in VR apps, which differentiates traditional mobile apps based on a smart phone device. Using exploratory text mining methods and network analysis approches, 241 apps registed in the Oculus Quest 2 App Store were analyzed. Analysis results from a quasi-network show that a leisure concept is closely related to various genre features including a game and tourism. Additionally, the anlaysis results of G & F model indicate that the leisure concept is distictive in the view of gateway brokerage role. Those results were also confirmed in LDA topic modeling analysis.

• Journal of the Korea Society of Computer and Information
• /
• v.14 no.9
• /
• pp.179-187
• /
• 2009

The national boundary's meanings turn to weak according to advent of Global enterprises. The place for design a product and marketing are separated to actual market. R&D is to the area where the knowledge activity is well, and low skilful product assembling is to the place the low wage is acceptable. It shows that the importance of net work structure. From early 90's, production system is diversified to markets where with the consumer as the central as multifarious items and creation new demands through consumer's participation into manufacturing process. This phenomenon show that logistics structures adapt to demand of technical variation, and the development of e-business with VAN(:value added network) and EDI(:Electronic data interchange) prove it. This study tried to analyze utilitarian assay about systems those land, sea, air logistics through documents research, and this study also present the direction of logistics system of airline company and goal of development on the based to the model of domestic airline company accordingly.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.33 no.3
• /
• pp.91-96
• /
• 2023

To verify the quality of bubbles during the use of quartz glass crucibles (QC), an appropriate accelerated testing method was proposed. The bubble state of discarded waste crucibles obtained from actual Czochralski (Cz) processes was analyzed, and optimal heat treatment conditions were suggested by varying temperature, pressure, and time using the QC test piece. By subjecting the samples to heat treatment at 1450℃, 0.4 Torr, and 40 hours, it was possible to control the bubble size and density to a similar level as those generated in the actual Cz process. In particular, by selecting a relatively lower pressure of 0.4 Torr compared to the typical range of 10~20 Torr applied in the Cz process, the time required for accelerated bubble formation testing could be reduced. However, it was determined that increasing the heat treatment temperature to 1550℃ led to the phenomenon of Ostwald ripening, resulting in larger bubbles and a rapid decrease in density. Therefore, it was concluded that it was not a suitable condition for the desired b ake test.

• Journal of the Korean Applied Science and Technology
• /
• v.37 no.3
• /
• pp.448-462
• /
• 2020

Dietary nutrition is a critical lifestyle factor that can reduce the risk of future cognitive impairments caused by dementia. Accumulating evidence suggests that dietary supplementation with Sulforaphane may help the prevention of cognitive impairments and dementia. Thus, Sulforaphane-enriched broccoli extract would hold promise to improve cognitive impairments of dementia patients. Here, we have used broccoli extracts, prepared from broccoli cultivated in Magma Seawater, to test if the broccoli extracts can be dietary supplement to improve cognitive impairments. Magma Seawater originated from Jeju Island, Korea is unique in terms of containing high concentrations of usable minerals (Zinc, Vanadium and Germanium etc.). Broccoli, grown in Magma Seawater, would contain Sulforaphane and the extra amount of usable minerals. The chemical compositions of the broccoli extracts were analyzed using LC-Q-orbitrap to detect Sulforaphane and Glucoraphanin. Analysis method based on HPLC was developed for measurement of sulforaphane levels in the broccoli extracts. We have tested if the broccoli extracts have anti-apoptotic and anti-inflammatory effects on neuron-like SH-SY5Y cells. In addition, we examined if the broccoli extracts are able to upregulate expression of synaptic plasticity-associated proteins (BDNF and phospho-CREB) and to inhibit acetylcholine esterase (AchE) activity. We have shown that the broccoli extracts inhibited the apoptotic pathway and inflammatory responses. Finally, we present evidence showing that AchE activity was inhibited by the broccoli extracts, but expression of BDNF and phospho-CREB was upregulated. Taken together, these findings suggest that the broccoli extracts from Magma Seawater-grown broccoli would be a good source of dietary nutrition to improve cognitive impairments in the future.