• Journal of Communications and Networks
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• v.9 no.3
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• pp.247-253
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• 2007

In this paper, downlink capacity of time duplex division (TDD) based cellular wireless networks utilizing fixed hopping stations is investigated. In the network, a number of fixed subscriber stations act as hopping transmission stations between base stations and far away subscribers, forming a cellular and ad hoc mobile network model. At the radio layer, TDD code division multiple access (CDMA) is selected as the radio interface due to high efficiency of frequency usage. In order to improve the system performance in terms of downlink capacity, we propose different time slot allocation schemes with the usage of fixed hopping stations, which can be selected by either random or distanced dependent schemes. Performance results obtained by computer simulation demonstrate the effectiveness of the proposed network to improve downlink system capacity.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.9
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• pp.3639-3662
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• 2020

The network capability to accomplish its functions in a timely fashion under failures and attacks is known as survivability. Ad hoc routing protocols have been studied and extended to various domains, such as Intelligent Transport Systems (ITSs), Unmanned Aerial Vehicles (UAVs), underwater acoustic networks, and Internet of Things (IoT) focusing on different aspects, such as security, QoS, energy. The existing solutions proposed in this domain incur substantial overhead and eventually become burden on the network, especially when there are fewer attacks or no attack at all. There is a need that the effectiveness of these routing protocols be analyzed in the presence of Denial of Service (DoS) attacks without any intrusion detection or prevention system. This will enable us to establish and identify the inherently stable routing protocols that are capable to survive longer in the presence of these attacks. This work presents a DoS attack case study to perform theoretical analysis of survivability on node and network level in the presence of DoS attacks. We evaluate the performance of reactive and proactive routing protocols and analyse their survivability. For experimentation, we use NS-2 simulator without detection or prevention capabilities. Results show that proactive protocols perform better in terms of throughput, overhead and packet drop.

• The Journal of the Korea Contents Association
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• v.20 no.5
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• pp.281-290
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• 2020

The purpose of this study was to examine how the consumer's entertainment, information, relevance, reliability, and perceived invasion affect the avoidance of advertising. Besides, the purpose of this study was to examine whether there is a difference according to the country and age in the effect of advertisement characteristics on the evasion. This study investigated the avoidance of mobile advertising among 254 Koreans and Chinese publics in their 20's and 40's, evaluated the results in terms of comparative analysis. Collected data were verified by multiple regression analysis and hierarchical regression analysis. The higher the advertising entertainment and relevance, the lower the avoidance of advertising. The higher the perceived penetration, the higher the avoidance of advertising. Besides, there were differences by country and age in the effects of advertising entertainment, information, relevance, and reliability on ad avoidance. The implications of this study are to find out how to reduce the mobile advertising avoidance of consumers by identifying the predictive factors that cause the avoidance of advertisements by country and age.

• The Journal of the Convergence on Culture Technology
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• v.6 no.2
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• pp.207-215
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• 2020

The purpose of this study is to examine the effectiveness of PBL in a college AD/PR class. This class was run under the theme of 'Sinchon Regeneration Project' in the 'Seodaemun-gu & University Collaborative Project Program'. As a result of the pre-post surveys, the authors found a significant increase in the place attachment to Sinchon, which was considered as a critical variable in this program. This research is an important study with high practicality in the area of cultural content production education PBL. The PBL teaching method can contribute to enhancing the class satisfaction and strengthening the competitiveness of students in cultural content related majors.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.11
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• pp.495-502
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• 2013

In this paper, we present an anonymous authentication and location assurance protocol for secure location-aware services over vehicular ad hoc networks (VANETs). In other to achieve our goal, we propose the notion of a location-aware signing key so as to strongly bind geographic location information to cryptographic function while providing conditional privacy preservation which is a desirable property for secure vehicular communications. Furthermore, the proposed protocol provides an efficient procedure based on hash chain technique for revocation checking to effectively alleviate communication and computational costs on vehicles in VANETs. Finally, we demonstrate comprehensive analysis to confirm the fulfillment of the security objectives, and the efficiency and effectiveness of the proposed protocol.

• Journal of the Korea Computer Industry Society
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• v.2 no.7
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• pp.983-996
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• 2001

Mobile Ad Hoc Network (MANET) is a network architecture which has no backborn network and is deployed temporarily and rapidly in emergency or war without fixed mobile infrastructures. All communications between network entities are carried in ad-hoc networks over the wireless medium. Due to the radio communications being extremely vulnerable to propagation impairments, connectivity between network nodes is not guaranteed. Therefore, previously developed routing algorithms in wired networks cannot be used. And many new algorithms have been undergone. This study proposes the Secondary Header approach to the cluster based routing protocol (CBRP). In case, the main header becomes abnormal status so that the main header can not participate the communications between network entities, the secondary header immediately replaces the primary header without selecting process of the new primary header. The performances of proposed algorithm CBRP-SH(Cluster Based Routing Protocol using Secondary Header) are compared with CBRP and results are presented in order to show the effectiveness of the algorithm.

• Clinical and Experimental Reproductive Medicine
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• v.48 no.4
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• pp.322-336
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• 2021

Objective: Endometriosis is a chronic debilitating inflammatory condition characterized by the presence of endometrial tissues outside the uterine cavity. Pelvic soreness and infertility are the usual association. Due to the poor effectiveness of the hormone therapy and the high incidence of recurrence following surgical excision, there is no single effective option for management of endometriosis. Mesenchymal stem cells (MSCs) are multipotent stromal cells studied for their broad immunoregulatory and anti-inflammatory properties; however, their efficiency in endometriosis cases is still a controversial issue. Our study aim was to evaluate whether adipose tissue-derived MSCs (AD-MSCs) could help with endometriosis through their studied anti-inflammatory role. Methods: Female Wistar rats weighting 180 to 250 g were randomly divided into two groups: group 1, endometriosis group; established by transplanting autologous uterine tissue into rats' peritoneal cavities and group 2, stem cell treated group; treated with AD-MSCs on the 5th day after induction of endometriosis. The proliferative activity of the endometriosis lesions was evaluated through Ki67 staining. Quantitative estimation of interferon γ, tumor necrosis factor-α, interleukin (IL)-6, IL-1β, IL-10, and transforming growth factor β expression, as well as immunohistochemical detection of CD68 positive macrophages, were used to assess the inflammatory status. Results: The size and proliferative activity of endometriosis lesions were significantly reduced in the stem cell treated group. Stem cells efficiently mitigated endometriosis associated chronic inflammatory reactions estimated through reduction of CD68 positive macrophages and the expression of the proinflammatory cytokines. Conclusion: Stem cell therapy can be considered a novel remedy in endometriosis possibly through its anti-inflammatory and antiproliferative properties.

• Journal of Digital Convergence
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• v.17 no.2
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• pp.37-45
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• 2019

This study investigated whether the model attributes of VR Ads (3D effect, presence, Dynamics, Amusement) affect the attitude of the advertising. We also examined the mediating role of consumer's innovation in the model attributes and advertising attitude of VR advertisements. To do this, VR equipment was used to induce real advertisers to experience advertisements. The causal relationship between variables was examined through covariance structure analysis. The results are as follows. First, all independent variables of the VR advertising model have a positive effect on the consumer's innovation. Second, the 3D effect, Amusement of the VR advertising model have a positive effect on the attitude of the advertising. Third, the effects of the VR advertising model on all variables are mediated by the consumer's innovation of the VR advertisement. The results of this study provide implications for understanding the characteristics of VR Ads.

• Journal of Oriental Neuropsychiatry
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• v.33 no.4
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• pp.401-424
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• 2022

Objectives: As effective treatments for dementia are lacking in Western medicine, complementary and alternative medicine (CAM) is considered a useful option. While the quality of life (QoL) is a vital outcome for patients with dementia, the QoL of patients receiving CAM for dementia remains ambiguous. This study aimed to determine the effect of CAM on QoL outcomes in dementia patients. Methods: A search was performed using the keywords "dementia," "Alzheimer's," "cognitive impairment," "Chinese," "Korean," "oriental," "herbal," "acupuncture," and "quality of life". All quantitative data were synthesized using R version 4.1.1. Results: Twenty-five randomized controlled trials (RCTs), 16 pre-post trials, and two cohort studies were selected for the systematic review. QoL in Alzheimer's disease (QOL-AD) (n=11, 25.6%) and geriatric QoL in dementia (GQOL-D, n=9, 20.9%) were the most utilized QoL instruments. Significant benefits in QoL were observed after receiving mind, body, combined mind and body, nursing, oriental medicine, and acupuncture therapies. In the meta-analysis, the combined effect was shown to significantly increase QOL-AD compared to before CAM interventions (standardized mean difference, SMD: 0.507; 95% confidence interval (CI), 0.191~0.824; p<0.01). The overall synthesized estimates in the GQOL-D showed a significantly improved QoL (SMD: 0.537, 95% CI: 0.238~0.837 p<0.01; one group; SMD: 1.465, 95% CI: 0.934~1.996, p<0.01). The seven studies assessing the cost-effectiveness of CAM reported uncertain outcomes. Conclusions: This study showed that CAM interventions benefited patients with dementia by improving their QoL. While additional standardized research is required, CAMs are suggested as effective clinical management for patients with dementia. They are also suggested as complementing therapies for these patients.

• Dementia and Neurocognitive Disorders
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• v.23 no.1
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• pp.54-66
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• 2024

Background and Purpose: Dementia subtypes, including Alzheimer's dementia (AD), dementia with Lewy bodies (DLB), and frontotemporal dementia (FTD), pose diagnostic challenges. This review examines the effectiveness of ¹⁸F-Fluorodeoxyglucose Positron Emission Tomography (¹⁸F-FDG PET) in differentiating these subtypes for precise treatment and management. Methods: A systematic review following Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines was conducted using databases like PubMed and Embase to identify studies on the diagnostic utility of ¹⁸F-FDG PET in dementia. The search included studies up to November 16, 2022, focusing on peer-reviewed journals and applying the goldstandard clinical diagnosis for dementia subtypes. Results: From 12,815 articles, 14 were selected for final analysis. For AD versus FTD, the sensitivity was 0.96 (95% confidence interval [CI], 0.88-0.98) and specificity was 0.84 (95% CI, 0.70-0.92). In the case of AD versus DLB, ¹⁸F-FDG PET showed a sensitivity of 0.93 (95% CI 0.88-0.98) and specificity of 0.92 (95% CI, 0.70-0.92). Lastly, when differentiating AD from non-AD dementias, the sensitivity was 0.86 (95% CI, 0.80-0.91) and the specificity was 0.88 (95% CI, 0.80-0.91). The studies mostly used case-control designs with visual and quantitative assessments. Conclusions: ¹⁸F-FDG PET exhibits high sensitivity and specificity in differentiating dementia subtypes, particularly AD, FTD, and DLB. This method, while not a standalone diagnostic tool, significantly enhances diagnostic accuracy in uncertain cases, complementing clinical assessments and structural imaging.