• Journal of KIISE:Information Networking
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• v.34 no.6
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• pp.514-524
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• 2007

Recent advances in the speed of multi-rate wireless local area networks (WLANs) and the proliferation of WLAN devices have made rate adaptive, opportunistic scheduling critical for throughput optimization. As WLAN traffic evolves to be more symmetric due to the emerging new applications such as VoWLAN, collaborative download, and peer-to-peer file sharing, opportunistic scheduling at the downlink becomes insufficient for optimized utilization of the single shared wireless channel. However, opportunistic scheduling on the uplink of a WLAN is challenging because wireless channel condition is dynamic and asymmetric. Each transmitting client has to probe the access point to maintain the updated channel conditions at the access point. Moreover, the scheduling decisions must be coordinated at all clients for consistency. This paper presents JUDS, a joint uplink/downlink opportunistic scheduling for WLANs. Through synergistic integration of both the uplink and the downlink scheduling, JUDS maximizes channel diversity at significantly reduced scheduling overhead. It also enforces fair channel sharing between the downlink and uplink traffic. Through extensive QualNet simulations, we show that JUDS improves the overall throughput by up to 127% and achieves close-to-perfect fairness between uplink and downlink traffic.

• Economic and Environmental Geology
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• v.42 no.3
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• pp.273-282
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• 2009

To render more valuable information, a spatial database is being constructed from digitalized maps in the geographic areas. Transferring file-based maps into a spatial database, facilitates the integration of larger databases and information retrieval using database functions. Geological mapping is the graphical interpretation results of the geological phenomenon by geological surveyors, which is different from other thematic maps produced quantitatively. These features make it difficult to construct geologic databases needing geologic interpretation about various meanings. For those reasons, several organizations in the USA and Australia are suggesting the data model for the database construction. But, it is hard to adapt to a domestic environment because of the representation differences of geological phenomenon. This paper suggests the data model adaptive in domestic environment analyzing 1:50,000 scales of geologic maps and more detailed mine geologic maps. The suggested model is a logical data model for the ArcGIS GeoDatabase. Using the model it can be efficiently applicable in the 1:50,000 scales of geological maps. It is expected that the geologic data model suggested in this paper can be used for integrated use and efficient management of geologic maps.

• Nuclear Engineering and Technology
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• v.25 no.1
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• pp.125-135
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• 1993

The safe and efficient operation of nuclear plants is recognized to be accomplished through the application of plant automation using digital technology, which is one of main targets of the next generation nuclear plants. For plant level automation, it is first required that each major subsystem be digitalized, and the steam generator water level control system is discussed in this study. The transfer functions between inputs and the level are derived by employing the thermal hydraulic model of the steam generator and are applied to the analysis of the current three-element control system. Since the control scheme in this study includes the steam generator itself as a process plant, the system order is high and the numerical instability arises in digitalizing. Together with this, the unreliability of the feedwater feedback signal at low power level leads to the proposal of a two-element control system with a proper digital controller. The digital PI controller developed for this system has the initial power adaptive gain and integration time constant. And it makes the overall system response satisfy the stability and other necessary control specifications simultaneously. Since the two-element control system using this controller depends on the initial power only, it is simple to define and it shows a similar level response behavior to that of its corresponding analog system.

• Korean Journal of School Psychology
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• v.17 no.2
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• pp.181-198
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• 2020

This study examined how the rejection sensitivity model might be applied to the link between rejection sensitivity and dating relationship satisfaction by means of investigating the mediating effect of cognitive emotion regulation strategy and conflict resolution strategy. A total of 668 college students in Seoul (232 males, 436 females, mean age of 21.59 years [SD=2.08]) participated in this study. The results illustrated that the adaptive emotion regulation strategy, among cognitive emotion regulation strategies, and the integration and compromise strategies, among conflict resolution strategies, had the double mediation effect on the association between rejection sensitivity and dating relationship satisfaction. In other words, a direct negative correlation between rejection sensitivity and dating relationship satisfation resulted in high rejection sensitivity, which was expected to generate low satisfaction in dating relationships. However, it was confirmed that the use of these two strategies-the cognitive emotion regulation and the conflict resolution strategy-could bring positive effects in terms of the dating relationship satisfaction; the former helped couples to see situations more broadly and increase positive perceptions, while the latter solve their problems each other. Based on these findings, we discuss their implications for counseling practice and therapeutic interventions

• IMMUNE NETWORK
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• v.22 no.3
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• pp.22.1-22.25
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• 2022

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndromecoronavirus-2 (SARS-CoV-2), has spread over the world causing a pandemic which is still ongoing since its emergence in late 2019. A great amount of effort has been devoted to understanding the pathogenesis of COVID-19 with the hope of developing better therapeutic strategies. Transcriptome analysis using technologies such as RNA sequencing became a commonly used approach in study of host immune responses to SARS-CoV-2. Although substantial amount of information can be gathered from transcriptome analysis, different analysis tools used in these studies may lead to conclusions that differ dramatically from each other. Here, we re-analyzed four RNA-sequencing datasets of COVID-19 samples including human bronchoalveolar lavage fluid, nasopharyngeal swabs, lung biopsy and hACE2 transgenic mice using the same standardized method. The results showed that common features of COVID-19 include upregulation of chemokines including CCL2, CXCL1, and CXCL10, inflammatory cytokine IL-1β and alarmin S100A8/S100A9, which are associated with dysregulated innate immunity marked by abundant neutrophil and mast cell accumulation. Downregulation of chemokine receptor genes that are associated with impaired adaptive immunity such as lymphopenia is another common feather of COVID-19 observed. In addition, a few interferon-stimulated genes but no type I IFN genes were identified to be enriched in COVID-19 samples compared to their respective control in these datasets. These features are in line with results from single-cell RNA sequencing studies in the field. Therefore, our re-analysis of the RNA-seq datasets revealed common features of dysregulated immune responses to SARS-CoV-2 and shed light to the pathogenesis of COVID-19.