• Journal of Communications and Networks
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• v.7 no.2
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• pp.144-156
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• 2005

Video streaming over wireless networks is challenging due to node mobility and high channel error rate. In this paper, we propose a multi-source video streaming (MUVIS) system to support high quality video streaming service over IEEE 802.1l-based wireless networks. We begin by collocating a streaming proxy with the wireless access point to help leverage both the media server and peers in the WLAN. By tracking the peer mobility patterns and performing content discovery among peers, we construct a multi-source sender group and stream video using a rate-distortion optimized scheme. We formulate such a multi-source streaming scenario as a combinatorial packet scheduling problem and introduce the concept of asynchronous clocks to decouple the problem into three steps. First, we decide the membership of the multisource sender group based on the mobility pattern tracking, available video content in each peer and the bandwidth each peer allocates to the multi-source streaming service. Then, we select one sender from the sender group in each optimization instance using asynchronous clocks. Finally, we apply the point-to-point rate-distortion optimization framework between the selected sender-receiver pair. In addition, we implement two different caching strategies, simple caching simple fetching (SCSF) and distortion minimized smart caching (DMSC), in the proxy to investigate the effect of caching on the streaming performance. To design more realistic simulation models, we use the empirical results from corporate wireless networks to generate node mobility. Simulation results show that our proposed multi-source streaming scheme has better performance than the traditional server-only streaming scheme and that proxy-based caching can potentially improve video streaming performance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.12
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• pp.4305-4323
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• 2014

In this paper, we investigate the degrees of freedom (DOF) of the Y channel consisting of three single-antenna users and a two-antenna common access relay, where each user intends to exchange independent messages with the other two users with the assistance of the relay. We show that the DOF of this particular scenario is 1.5. In order to prove this result, we firstly derive a DOF upper bound based on cut-set bound by allowing cooperation among users, which shows that the total DOF is upper bounded by 1.5. Then we propose a novel transmission scheme based on asymmetric signal space alignment (ASSA) to demonstrate the achievability of the upper bound. Theoretical evaluation and numerical results confirm that the upper bound can be achieved by utilizing ASSA, which also proves the optimality of the ASSA-based scheme in terms of DOF. Combining the upper bound and achievability, we conclude that the exact DOF is 1.5. Moreover, we present a novel iterative joint beamforming optimization (I-JBO) algorithm to further improve the sum rate. Numerical simulations have been provided to demonstrate the convergence speed and performance advantage of the I-JBO algorithm.

• The Journal of Korean Academic Society of Nursing Education
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• v.21 no.1
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• pp.54-64
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• 2015

Purpose: The purpose of this study was to investigate the effects of simulation in nursing education based on caring for elderly cognition disorder patients. The education consisted of a caring program for patients that included a process of assessment of a patient's mental status, diagnosis of the patient's health condition, and intervention to address the problems by using therapeutic communication. Methods: A nonequivalent control group pretest-posttest design was used. A total of 69 subjects (undergraduate students) participated in the education and they were assigned to two groups: the experimental group (n=32) and the control group (n=37). Data-gathering structured questionnaires that included communication competence, academic self-efficacy, and attitudes about the elderly. The data were collected from October 2013 to December 2013, and statistical analyses were conducted with-test and t-test using the SPSS 21.0 program. Results: With respect to education, there was significant improvement in communication competence in the experiment group (t=2.41, p=.022) compared with in the control group (t=.69, p=.494). However, there was no statistically significant difference in academic self-efficacy and attitude about the elderly. Conclusion: Simulation-based education should continue to be developed further for better elderly-patient care. Integrated education in particular using a high-fidelity simulator will contribute to improvements in nursing competence in this area.

• Journal of the Korean Geographical Society
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• v.44 no.3
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• pp.372-394
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• 2009

This study investigates the ontology-based public participation GIS(PPGIS). The major reason that ontology-based GIS has attracted attention in semantic communication in recent year is due to the wide availability of geographical variable and the imminent need for turning such recommendation into useful geographical knowledge. Therefore, this study has been focused on designing and implementing the pilot tested system for public participation GIS. The applicability of the pilot tested was validated through a simulation experiment for history tourism in Guri city Gyeongi-do, Focused on the methodology, the life cycle model which involves regional statues and user recognition, can be viewed as an important preprocessing step(specification, conceptualization, formalization, integration and implementation) for recommended geographical knowledge discovery by axiom. Focusing on practicality, ontology in this study would be recommended for geographical knowledge through reasoning. In addition, ontology-based public participation GIS would show integration epistemological and ontological approach, and be utilized as an index which is connected with semantic communication. The results of the pilot system was applied to the study area, which was a part of scenario. The model was carried out using axiom of logical constraint in the meaning of human-activity.

• Asia pacific journal of information systems
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• v.34 no.2
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• pp.518-540
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• 2024

Mobile technologies have enabled marketers to target consumers anywhere and anytime. However, as consumers react and respond differently depending on what situation they are in, there is an apparent need to determine when, where, and what kind of advertisement is most relevant to the consumer. This paper proposes a holistic approach to examine the response of consumers when faced with two types of contextual factors (environmental/spatial and social contexts) through the lens of the Mobile Advertising Effectiveness Framework. We focus on the contextual effects of perceived distance from the offline store and the effect of popularity cue indication. A scenario-based survey is conducted to investigate the effects of perceived distance and popularity cue on the users' attitudes, and ultimately on their response intentions, upon receipt of mobile ads. Results of the study confirm the hypotheses: first, mobile ads sent when users perceive the physical store to be in close proximity tend to evoke more positive attitudes and elicit better responses compared to when users perceive the store to be farther away. Additionally, ad messages indicating high popularity were found to be more appealing than those with low popularity. These empirical results underscore the pivotal role of context, encompassing both spatial context (proximity to offline stores) and social context (popularity cues), in shaping consumer attitudes and response intentions in mobile advertising. The findings of the study offer theoretical insights that underline the significance of holistic context-based approaches that in turn, marketers may use to design more effective mobile ad campaigns that may elicit better responses from consumers.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.8
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• pp.2814-2832
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• 2014

As information society matures to an even higher level and as information technology becomes a necessity to our everyday lives, the needs to develop, support and satisfy personal and social needs without the limitation of time, space, and location have become a vital point to everyday lives. Smartphone users are increasing at a staggering rate but the research on mobile-Learning model and the implementation of m-Learning scenario are still behind the needs of the users. Therefore, this paper focuses on the design of 'repeatable and short-spanned m-Learning model' to meet the needs of the learners who are on the go and on the move with their smartphones. Smartphone users frequently reach out for their phones but compare to the frequencies, the actual span of time they spend per use are relatively and surprisingly short. One way to understand this phenomenon is that the users tend to immediately replace their smartphones with laptops or desktops whenever they are available. A leaning model was needed to reflect this short and frequent use, a use that is solely based on the smartphone environment. This proposed learning model first defines this particular setting and implements the model to real smartphone users over an 8 week period. To understand whether different learning backgrounds can influence this model, different schools with online and offline learning channels participated in the experiment. User survey was conducted after the experiment to get a better understanding of the smartphone users. Pretest and posttest were conducted before and after the experiment and the data were validated and analyzed using SPSS version 18.0 for PC. Preliminary descriptive statistics, multiple regression and cross validation was conducted for the analysis. The results showed that the proposed English Listening and Comprehension Mobile Digital Textbook (ELCMDT) had a positive effect on the learners in general and was more effective for learners who were already experienced with online learning.

• Journal of the Korea Society for Simulation
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• v.28 no.4
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• pp.33-43
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• 2019

Link-16 is a data link that provides joint interoperability to the US Navy, Air Force and NATO. Currently, the military relies entirely on foreign SW and tools for test environment, tactical simulation training and interoperability verification test for Link-16 operation. Therefore, it is necessary to develop Link-16 based operation environment test tool. In this paper, Link-16 network operational performance analysis simulator was developed by analyzing the function of Link-16 foreign tools. It also implements the SIMPLE standard interface for interworking with foreign SW and tools. The functional model for Link-16 network operation performance analysis consists of pre-analysis, real-time operational analysis, and post-analysis functional model. Each functional model test was performed through SIMPLE interworking with foreign SW and tools. Link-16 network operation performance analysis If we replace foreign SW through simulator, we can perform tactical training, network design verification and operation (scenario) verification for our military.

• Journal of KIISE:Information Networking
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• v.34 no.1
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• pp.16-26
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• 2007

It is well known that, in the near future, the lifetime of the IPv4 address space will be limited and available 32-bit IP network addresses will not be left my more. In order to solve such IPv4 address space problem in an effective way, the transition to the new version using IPv6 architecture is inevitably required. This paper presents the design and implementation of IPv4/IPv6 dual stack at the GSM Phone based on Linux Kernel 2.4 IPv6 Protocol Stack. It designs appropriately in GSM Phone environment and it is tested by a network of Linux IPv4/IPv6 dual stack on PPP. The test was processed with a test scenario and it was found that the results were successful.

• Steel and Composite Structures
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• v.15 no.1
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• pp.103-130
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• 2013

Fire performance and fire safety of high-rise buildings have become major concerns after the disasters of World Trade Center in the U.S. in 2001 and Windsor tower in Spain in 2005. Performance based design (PBD) approaches have been considered as a better method for fire resistance design of structures because it is capable of incorporating test results of most recent fire resistance technologies. However, there is a difficulty to evaluate fireproof performance of large structures, which have multiple structural members such as columns, slabs, and walls. The difficulty is mainly due to the limitation in the testing equipment, such as size of furnace that can be used to carry out fire tests with existing criteria like ISO 834, BS 476, and KS F 2257. In the present research, a large scale calorie meter (10 MW) was used to conduct three full scale fire tests on medical modular blocks. Average fire load of 13.99 $kg/m^2$ was used in the first test. In the second test, the weighting coefficient of 3.5 (the fire load of 50 $kg/m^2$) was used to simulate the worst fire scenario. The flashover of the medical modular block occurred at 62 minutes in the first test and 12 minutes in the second test. The heat resistance capacity of the external wall, the temperatures and deformations of the structural members satisfied the requirements of fire resistance performance of 90 minutes burning period. The total heat loads and the heat values for each test are calculated by theoretical equations. The duration of burning was predicted. The predicted results were compared with the test results, and they agree quite well.

• The Journal of Industrial Distribution & Business
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• v.11 no.6
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• pp.19-28
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• 2020

Purpose: Current study aimed at exploring the effects of ambient anger versus sadness on motive type and coping strategy type when consumers make decision. It focused on whether the negative affects of the anger and the sadness differentially induce approach versus avoidance motive at the place of making decision, and also explored the coping strategy differences between the consumers under the anger and those under the sadness, that is, which strategy is more used between problem-focused strategy and affect-focused strategy when they are under each negative affect. Research design, data and methodology: The experimental groups were divided into two types of group such as the anger-felt group and the sadness-felt group. The experiment was performed with the between-subjects design based on the anger and the sadness. Questionnaire data were collected from undergraduate students assigned to each of the anger group and the sadness group operated by the scenario method, and the data were used to verify research hypotheses by t-test. Results: - First, the anger induced the approach motive more rather than the avoidance motive in making decision. Second, to cope the negative affects, consumers under the anger used problem-focused strategy more than affect-focused strategy, while those under the sadness used affect-focused strategy more than problem-focused strategy. Therefore, this article contributes to the theory related to motive and making decision taken place to consumers under ambient negative emotions. Conclusions: Focusing on the results of this study, there could be managerial implications to brand or product marketing managers. Checking which affect consumers previously felt between anger and sadness when they are under negative affects is at issue to the brand or product marketers when they appeal their brand or product to the consumers. The marketers should build and communicate the messages about their product or brand in the respect of the points of showing problem solution or the best way to handle things to appeal the consumers under the anger. And they should develop and communicate the messages about their product or brand emphasizing the aspects of letting consumers' sad feelings out somehow or controlling their emotions to the consumers under sadness.