• IEMEK Journal of Embedded Systems and Applications
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• v.19 no.3
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• pp.123-130
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• 2024

This paper proposes an EMPC (Explicit Model Predictive Controller) for temperature tracking control based on heat load prediction by an ESO (Extended State Observer) for a variable cooling circulation system with multiple indoor units connected to one outdoor unit. In this system, heat transfer and heat loss relative to the input temperature are modeled using system dynamics. Using this model, we design an EMPC based on an ESO that is robust to temperature changes and depends on airflow. To determine the stability of both the controller and the observer, asymptotic stability is verified through Lyapunov stability analysis. Finally, to validate the performance of the proposed controller, simulations are conducted under three scenarios with varying airflow, set temperature, and heat load.

• IEMEK Journal of Embedded Systems and Applications
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• v.19 no.3
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• pp.141-149
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• 2024

This paper proposes a configuration automation technique to minimize service interruption time in the event of a corporate network access layer switch failure. The automation is achieved without the need for a separate external system, as the network setting information is stored in a container inside the switch, enabling rapid recovery without requiring separate storage. This approach ensures the continuity of network services and demonstrates the efficiency of configuration automation. The proposed technique improves corporate network stability by providing a quick response in the event of a failure.

• IMMUNE NETWORK
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• v.20 no.3
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• pp.20.1-20.15
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• 2020

Memory CD8+ T cells in the immune system are responsible for the removal of external Ags for a long period of time to protect against re-infection. Naïve to memory CD8+ T cell differentiation and memory CD8+ T cell maintenance require many different factors including local environmental factors. Thus, it has been suggested that the migration of memory CD8+ T cells into specific microenvironments alters their longevity and functions. In this review, we have summarized the subsets of memory CD8+ T cells based on their migratory capacities and described the niche hypothesis for their survival. In addition, the basic roles of CCR7 in conjunction with the migration of memory CD8+ T cells and recent understandings of their survival niches have been introduced. Finally, the applications of altering CCR7 signaling have been discussed.

• Journal of Information Technology Applications and Management
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• v.31 no.4
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• pp.1-14
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• 2024

Sustainable consumption is the consumer's preference for the products that are environmentally friendly however, non-consumption also plays a major role in sustainability. A counter movement of anti-consumption runs from the beginning of mass-consumption of societies. Consumers can choose not to consume products/brands that can cause a harm to the environment or are incompatible with their ideology on conservation. The underlying notion of these non-consumption practices or anti-consumption is that the consumer is concerned about the effects that a purchasing choice has, not only on themselves but also on the external world. Anti-consumption is a resistance to, distaste of or even resentment of consumption. There is low adaptation rate of green consumption in terms of household products which shows that the non-green consumers reflect the mainstream population and indicates that consumers following anti-consumption is a niche segment reflecting the need of research in this area. So it is consequential to explore the available literatures regarding the subject matter and conduct a quantitative study. Following the notion this paper aims analyzing the factors influencing the anti-consumption behavior of household products in Nepalese context.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.375-375
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• 2012

Graphene is a sp2-hybridized carbon sheet with an atomic-level thickness and a wide range of graphene applications has been intensely investigated due to its unique electrical, optical, and mechanical properties. In particular, hybrid graphene structures combined with various nanomaterials have been studied in energy- and sensor-based applications due to the high conductivity, large surface area and enhanced reactivity of the nanostructures. Conventional metal-catalytic growth method, however, makes useful applications difficult since a transfer process, used to separate graphene from the metal substrate, should be required. Recently several papers have been published on direct graphene growth on the two dimensional planar substrates, but it is necessary to explore a direct growth of hierarchical nanostructures for the future graphene applications. In this study, uniform graphene layers were successfully synthesized on highly dense dielectric nanowires (NWs) without any external catalysts. We also demonstrated that the graphene morphology on NWs can be controlled by the growth parameters, such as temperature or partial pressure in chemical vapor deposition (CVD) system. This direct growth method can be readily applied to the fabrication of nanoscale graphene electrode with designed structures because a wide range of nanostructured template is available. In addition, we believe that the direct growth growth approach and morphological control of graphene are promising for the advanced graphene applications such as super capacitors or bio-sensors.

• Journal of Microbiology and Biotechnology
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• v.29 no.10
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• pp.1607-1623
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• 2019

Sediment bioelectrochemical systems (SBESs) can be integrated into brackish aquaculture ponds for in-situ bioremediation of the pond water and sediment. Such an in-situ system offers advantages including reduced treatment cost, reusability and simple handling. In order to realize such an application potential of the SBES, in this laboratory-scale study we investigated the effect of several controllable and uncontrollable operational factors on the in-situ bioremediation performance of a tank model of a brackish aquaculture pond, into which a SBES was integrated, in comparison with a natural degradation control model. The performance was evaluated in terms of electricity generation by the SBES, Chemical oxygen demand (COD) removal and nitrogen removal of both the tank water and the tank sediment. Real-life conditions of the operational parameters were also experimented to understand the most close-to-practice responses of the system to their changes. Predictable effects of controllable parameters including external resistance and electrode spacing, similar to those reported previously for the BESs, were shown by the results but exceptions were observed. Accordingly, while increasing the electrode spacing reduced the current densities but generally improved COD and nitrogen removal, increasing the external resistance could result in decreased COD removal but also increased nitrogen removal and decreased current densities. However, maximum electricity generation and COD removal efficiency difference of the SBES (versus the control) could be reached with an external resistance of $100{\Omega}$, not with the lowest one of $10{\Omega}$. The effects of uncontrollable parameters such as ambient temperature, salinity and pH of the pond (tank) water were rather unpredictable. Temperatures higher than $35^{\circ}C$ seemed to have more accelaration effect on natural degradation than on bioelectrochemical processes. Changing salinity seriously changed the electricity generation but did not clearly affect the bioremediation performance of the SBES, although at 2.5% salinity the SBES displayed a significantly more efficient removal of nitrogen in the water, compared to the control. Variation of pH to practically extreme levels (5.5 and 8.8) led to increased electricity generations but poorer performances of the SBES (vs. the control) in removing COD and nitrogen. Altogether, the results suggest some distinct responses of the SBES under brackish conditions and imply that COD removal and nitrogen removal in the system are not completely linked to bioelectrochemical processes but electrochemically enriched bacteria can still perform non-bioelectrochemical COD and nitrogen removals more efficiently than natural ones. The results confirm the application potential of the SBES in brackish aquaculture bioremediation and help propose efficient practices to warrant the success of such application in real-life scenarios.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.239-245
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• 2016

In this study, a 12 V PWM boost converter was designed with the optimal values of the external components of the power stage was well as the compensation stage for smart electronic applications powered by a battery device. The 12 V boost PWM converter consisted of several passive elements, such as a resistor, inductor and capacitor with a diode, power MOS switch and control IC chip for the control PWM signal. The devices of the power stage and compensation stage were designed to maintain stable operation under a range of load conditions as well as achieving the highest power efficiency. The results of this study were first verified by a simulation in SPICE from calculations of the values of major external elements comprising the converter. The design was also implemented on the prototype PCBboard using commercial IC LM3481 from Texas Instruments, which has a nominal output voltage of 12 V. The output voltage, ripple voltage, and load regulation with the line regulation were measured using a digital oscilloscope, DMM tester, and DC power supply. By configuring the converter under the same conditions as in the circuit simulation, the experimental results matched the simulation results.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.5
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• pp.629-635
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• 2010

An SGBEM (symmetric Galerkin boundary element method)-FEM alternating method has been proposed by Nikishkov, Park and Atluri. This method can be used to obtain mixed-mode stress intensity factors for planar and nonplanar three-dimensional cracks having an arbitrary shape. For field applications, however, it is necessary to verify the accuracy and consistency of this method. Therefore, in this study, we investigate the effects of several factors on the accuracy of the stress intensity factors obtained using the abovementioned alternating method. The obtained stress intensity factors are compared with the known values provided in handbooks, especially in the case of internal and external circumferential semi-elliptical surface cracks. The results show that the SGBEM-FEM alternating method yields accurate stress intensity factors for three-dimensional cracks, including internal and external circumferential surface cracks and that the method can be used as a robust crack analysis tool for solving field problems.

• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.1
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• pp.107-117
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• 2011

This study aimed to inquire into possibilities of the web-based representation of thematic maps by geo-information mashup in the geoweb platform. In the Web2.0, Google platform leads the geoweb by offering effective mashup functions for geo-information. Geo-information mashup is opening a new horizon of map applications in fusion with a great of data in the Internet. Geo-information mashup by the available data method can be classified as two type; one is linkage of sources of platform itself(satellite images) and external data, the other is linkage of platform itself and user created contents. This study made heatmap, proportional map, and choropleth map based on Google satellite images by the linkage of platform itself and external data. As a result, thematic map of Google mashup expected to give us to a flexibility for difference interpretations of geographical distribution by representing overlap with satellite images.

• Journal of the Korea Society of Computer and Information
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• v.25 no.3
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• pp.89-96
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• 2020

Solar lamp systems may not operate normally in the event of some system or controller failure due to internal or external factors, in which case secondary problems occur, which may cost the system recovery. Thus, when these errors occur, a technology is needed to recover to the state it was in before the failure occurred and to enable re-execution. This paper designs and implements a system that can recover the state of the system to the state prior to the time of the error by using the Watchdog Timer within the controller if a software error has occurred inside the system, and it also proposes a technology to reset and re-execution the system through a separate reset circuit in the event of hardware failure. The proposed system provides stable operation, maintenance cost reduction and reliability of the solar lamp system by enabling the system to operate semi-permanently without external support by utilizing the automatic recovery and automatic reset function for errors that occur in the operation of the solar lamp system. In addition, it can be applied to maintain the system's constancy by utilizing the self-operation, diagnosis and recovery functions required in various high reliability applications.