• KNOM Review
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• v.24 no.1
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• pp.1-12
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• 2021

VM (Virtual Machine) live migration is a server virtualization technique for deploying a running VM to another server node while minimizing downtime of a service the VM provides. Currently, in cloud data centers, VM live migration is widely used to apply load balancing on CPU workload and network traffic, to reduce electricity consumption by consolidating active VMs into specific location groups of servers, and to provide uninterrupted service during the maintenance of hardware and software update on servers. It is critical to use VMlive migration as a prevention or mitigation measure for possible failure when its indications are detected or predicted. In this paper, we propose two VNF live migration methods; one for predictive load balancing and the other for a proactive measure in failure. Both need machine learning models that learn periodic monitoring data of resource usage and logs from servers and VMs/VNFs. We apply the second method to a vEPC (Virtual Evolved Pakcet Core) failure scenario to provide a detailed case study.

• Journal of Satellite, Information and Communications
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• v.9 no.3
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• pp.109-115
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• 2014

This paper suggest meteorological satellite processing software's structure that reduces time and efforts of modification/upgrade. This structure's key feature is "algorithm component" that works within framework and eventually to a complete Meteorological satellite processing system. Most of existing Meteorological satellite system is designed around specific function and data sets which limits range of modification and upgrade. In addition, re-use of current algorithms become difficult although re-use of similar algorithm is the case in many occasions. This inefficiency can be resolved by designing a new framework as a result of detail analysis of collected requirements. A new framework and system architecture has been designed. In addition, operational flow of Satellite image processing framework has been described.

• Journal of Information Technology Services
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• v.14 no.2
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• pp.315-335
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• 2015

The New Way of Working (NWOW) is changing the world in which we work today. The principles of NWOW are based on freedom of time and place to work, and steering on output (results) instead of input (presence). As NWOW is a relatively new phenomenon, research on the effect of NWOW on knowledge sharing in organizations is scarce. In this research two multiple-case studies were performed to investigate the effect of the New Way of Working on knowledge. In the first study (A) different knowledge sharing scenarios were used at organizations that were in the process of implementing NWOW. This provided the opportunity to compare the sharing of knowledge between 'NWOW workers' and employees that still worked in the traditional way (non-NWOW workers). In total 216 scenario results were evaluated to determine differences in channel choice between the traditional and new work environment. For the second study (B) a Knowledge Sharing Framework was developed, based on the theories of Nonaka and Alavi & Leidner. This framework was used to determine the type of knowledge shared, e.g. tacit or explicit knowledge, in 84 situations. Additionally, to measure the level of NWOW adoption, a NWOW Analysis Monitor was used. The results show that NWOW workers use more different communication channels than traditional workers. When knowledge workers become more mobile, they will exchange knowledge less explicit (codified) and more tacit (personalized), use less face-to-face communication, but more video calls and e-mail. The adoption of the principles of NWOW seems to have a balancing effect on the knowledge that is shared in a tacit and explicit way, which in the view of Scheepers et al. is an effective knowledge sharing strategy. The research results show organizations need to realize that the New World of Working is affecting the way knowledge is shared. Missing out on this development may result in the loss of important knowledge and impact the operation of organizations.

• Journal of the Economic Geographical Society of Korea
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• v.15 no.4
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• pp.615-627
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• 2012

This study analyzed the travel pattern with respect to use of public transportation by using transportation card data and presented the measures that can be used in a traffic policy. Transportation card data targeted Gyeonggi-Do area and as a utilization plan, a scenario that when a traffic policy decision maker improves bus stop facilities, the person selects a target site by using several variables that can be obtained from transportation card data was set and analyzed. The analysis result showed that K means cluster analysis which is decision making methodology and CHAID(Chi-squared automatic interaction detection) were used and it can be used usefully in policies in significance level of p <0.01. Also, based on these results, this study presented policy implications to be improved to actually use transportation card data in policies.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.57.2-57.2
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• 2014

Red active galactic nuclei (AGNs) are supposed to be transitional objects becoming normal AGNs in the galaxy evolution scenario. So far, ~200 red AGNs have been found by very red color in optical through NIR wavelength (e.g., r'-K >5 and J-K>1.3; Urrutia et al. 2009). Here, we compare nuclear activities of the red AGNs to those of normal AGNs to verify the evolutionary phase of the red AGNs. In order to study the nuclear activities of the red AGNs, we use broad emission lines of $P{\beta}$ ($1.28{\mu}m$) of which flux is less suppressed by a factor of 100 than the $H{\beta}$ line in the case of the red AGNs with a color excess of E(B-V)=2 mag. We use 16 red AGNs discovered in previous red AGN surveys by using SDSS, 2MASS, and FIRST (Glikman et al. 2007; Urrutia et al. 2009) at z ~0.7 for which $P{\beta}$ lines are redshifted to the sky window at ${\sim}2.2{\mu}m$. The mean Eddington ratio of the 16 red AGNs is 0.562, and that of the normal AGNs is 0.320, which indicates the red AGNs include more active black hole (BH) than the normal AGNs. To test how significantly the nuclear activities of the red AGNs and the normal AGNs are different, we perform a two-dimensional Kolmogorov-Smirnov test (K-S test) on their Eddington ratio distributions. The K-S test shows the maximum deviation between the cumulative distributions, D, is 0.48, and the probability of null hypothesis, p, is even less than 0.001. This result is consistent with a picture of that the red AGNs are in intermediate phase between the stage of merger-driven starburst galaxy and the normal AGN.

• Journal of Communications and Networks
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• v.11 no.6
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• pp.574-588
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• 2009

Although much research has been conducted in the area of authentication in wireless networks, vehicular ad-hoc networks (VANETs) pose unique challenges, such as real-time constraints, processing limitations, memory constraints, frequently changing senders, requirements for interoperability with existing standards, extensibility and flexibility for future requirements, etc. No currently proposed technique addresses all of the requirements for message and entity authentication in VANETs. After analyzing the requirements for viable VANET message authentication, we propose a modified version of TESLA, TESLA++, which provides the same computationally efficient broadcast authentication as TESLA with reduced memory requirements. To address the range of needs within VANETs we propose a new hybrid authentication mechanism, VANET authentication using signatures and TESLA++ (VAST), that combines the advantages of ECDSA signatures and TESLA++. Elliptic curve digital signature algorithm (ECDSA) signatures provide fast authentication and non-repudiation, but are computationally expensive. TESLA++ prevents memory and computation-based denial of service attacks. We analyze the security of our mechanism and simulate VAST in realistic highway conditions under varying network and vehicular traffic scenarios. Simulation results show that VAST outperforms either signatures or TESLA on its own. Even under heavy loads VAST is able to authenticate 100% of the received messages within 107ms. VANETs use certificates to achieve entity authentication (i.e., validate senders). To reduce certificate bandwidth usage, we use Hu et al.'s strategy of broadcasting certificates at fixed intervals, independent of the arrival of new entities. We propose a new certificate verification strategy that prevents denial of service attacks while requiring zero additional sender overhead. Our analysis shows that these solutions introduce a small delay, but still allow drivers in a worst case scenario over 3 seconds to respond to a dangerous situation.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.486-486
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• 2018

During the post green revolution era, wheat and rice were the main crops of concern to cater the food security issues of Pakistan. The use of semi dwarf high yielding varieties along with extensive use of fertilizers and surface and ground water lead to substantial increase in crop production. However, the higher crop productivity came at the cost of over exploitation of the precious land and water resources, which ultimately has resulted in the dwindling production rates, loss of soil fertility, and qualitative and quantitative deterioration of both surface and ground water bodies. Recently, during the past two decades, severe climate changes are further pushing the Pakistan's wheat-rice system towards its limits. This necessitates a careful analysis of the current crop water requirements and water footprints (both green and blue) to project the future trends under the most likely climate change phenomenon. This was done by using the FAO developed CROPWAT model v 8.0, coupled with the statistically-downscaled climate projections from the 8 Global Circulation Models (GCMs), for the two future time slices, 2030s (2021-2050) and 2060s (2051-2080), under the two Representative Concentration Pathways (RCPs): 4.5 and 8.5. The wheat-rice production system of Punjab, Pakistan was considered as a case study in exploration of how the changing climate might influence the crop water requirements and water footprints of the two major crops. Under the worst, most likely future scenario of temperature rise and rainfall reduction, the crop water requirements and water footprints, especially blue, increased, owing to the elevated irrigation demands originating from the accelerated evapotranspiration rates. A probable increase in rainfall as envisaged by some GCMs may partly alleviate the adverse impacts of the temperature rise but the higher uncertainties associated with the predicated rainfall patterns is worth considering before reaching a final conclusion. The total water footprints were continuously increasing implying that future climate would profoundly influence the crop evapotranspiration demands. The results highlighted the significance of the irrigation water availability in order to sustain and improve the wheat-rice production system of Punjab, Pakistan.

• Management & Information Systems Review
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• v.37 no.4
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• pp.195-217
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• 2018

Inaction inertia effect refers to the phenomenon wherein people who missed attractive opportunities in the past do not take any action when they are given the opportunity to receive discounts (sale). The main objective of this study was to find out how such inaction inertia effect influenced the expected regret from the action, expected regret from inaction, and purchase intention depending on the two types of consumption purposes-for pleasure and for practical use. As the personal disposition of each consumer differs from one another, it was expected that habitual purchase behavior and maximization behavior would influence the inaction inertia. An experiment was thus conducted by using a scenario to satisfy the objective of this study. Results showed that in the case of consumers whose consumption purpose was for pleasure, those who habitually purchased the same brand showed a higher level of expected regret from the action and expected regret from inaction. In the case of maximization behavior, no differences were found in the expected regret from the action between practical consumption purpose and pleasurable consumption purpose. On the other hand, differences were found in the level of expected regret from inaction, which is the case wherein consumers who missed their first opportunity to receive discounts (sale) did not make any purchase on their second opportunity for discounts (sale). Thus, inaction inertia was shown in accordance with habitual purchase behavior in the case of consumption purpose for pleasure, but it was not clearly shown in the case of consumption for practical use. This is because there is a relatively low level of justification on consumption, in the case of consumption for practical use. On the other hand, it was found that consumers with maximization behavior felt a stronger sense of regret in the case of their expected regret for inaction in consumption for practical use than in consumption for pleasure. Also, with regard to purchase intention, it turned out that only consumers with pleasurable consumption purpose had purchase intentions. Through these study results, it would be necessary to consider the consumption purpose behind the purchase of products or services, with regard to inaction inertia, depending on personal dispositions. In accordance with these study results, several theoretical and practical implications were discussed.

• The Journal of the Convergence on Culture Technology
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• v.9 no.6
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• pp.1143-1149
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• 2023

The purpose of this study was to the effects of case-based learning (CBL) on problem solving ability and academic self-efficacy in nursing students and was a quasi-experimental study with a one-group pretest-posttest design. The subjects of this study were 121 grade 4 students, and the data collection period was from Aprill 24 to June 12, 2023. The research procedure was scenario development, preliminary investigation, application of case-based learning classes, and follow-up investigation, and the CBL was conducted for 2 weeks, 50 minutes per week. The general characteristics of the subjects were obtained by frequency, percentage, mean, and standard deviation and the effects of CBL on problem solving ability and academic self-efficacy was tested using a paired t-test. The results of this study showed that nursing students' problem solving ability (t=-5.70, p<.001) and academic self-efficacy (t=-3.25, p<.002) improved after applying CBL compared to before applying it. We suggest the use of case-based learning as a strategy to improve problem-solving skills and academic self-efficacy in nursing education. In the future, follow-up research is needed to verify the effectiveness by developing and applying step-by-step clinical cases at an appropriate level according to the learning content of nursing major subjects by grade.

• Journal of Intelligence and Information Systems
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• v.22 no.1
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• pp.107-118
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• 2016

The advent of 5G mobile communications, which is expected in 2020, will provide many services such as Internet of Things (IoT) and vehicle-to-infra/vehicle/nomadic (V2X) communication. There are many requirements to realizing these services: reduced latency, high data rate and reliability, and real-time service. In particular, a high level of reliability and delay sensitivity with an increased data rate are very important for M2M, IoT, and Factory 4.0. Around the world, 5G standardization organizations have considered these services and grouped them to finally derive the technical requirements and service scenarios. The first scenario is broadcast services that use a high data rate for multiple cases of sporting events or emergencies. The second scenario is as support for e-Health, car reliability, etc.; the third scenario is related to VR games with delay sensitivity and real-time techniques. Recently, these groups have been forming agreements on the requirements for such scenarios and the target level. Various techniques are being studied to satisfy such requirements and are being discussed in the context of software-defined networking (SDN) as the next-generation network architecture. SDN is being used to standardize ONF and basically refers to a structure that separates signals for the control plane from the packets for the data plane. One of the best examples for low latency and high reliability is an intelligent traffic system (ITS) using V2X. Because a car passes a small cell of the 5G network very rapidly, the messages to be delivered in the event of an emergency have to be transported in a very short time. This is a typical example requiring high delay sensitivity. 5G has to support a high reliability and delay sensitivity requirements for V2X in the field of traffic control. For these reasons, V2X is a major application of critical delay. V2X (vehicle-to-infra/vehicle/nomadic) represents all types of communication methods applicable to road and vehicles. It refers to a connected or networked vehicle. V2X can be divided into three kinds of communications. First is the communication between a vehicle and infrastructure (vehicle-to-infrastructure; V2I). Second is the communication between a vehicle and another vehicle (vehicle-to-vehicle; V2V). Third is the communication between a vehicle and mobile equipment (vehicle-to-nomadic devices; V2N). This will be added in the future in various fields. Because the SDN structure is under consideration as the next-generation network architecture, the SDN architecture is significant. However, the centralized architecture of SDN can be considered as an unfavorable structure for delay-sensitive services because a centralized architecture is needed to communicate with many nodes and provide processing power. Therefore, in the case of emergency V2X communications, delay-related control functions require a tree supporting structure. For such a scenario, the architecture of the network processing the vehicle information is a major variable affecting delay. Because it is difficult to meet the desired level of delay sensitivity with a typical fully centralized SDN structure, research on the optimal size of an SDN for processing information is needed. This study examined the SDN architecture considering the V2X emergency delay requirements of a 5G network in the worst-case scenario and performed a system-level simulation on the speed of the car, radius, and cell tier to derive a range of cells for information transfer in SDN network. In the simulation, because 5G provides a sufficiently high data rate, the information for neighboring vehicle support to the car was assumed to be without errors. Furthermore, the 5G small cell was assumed to have a cell radius of 50-100 m, and the maximum speed of the vehicle was considered to be 30-200 km/h in order to examine the network architecture to minimize the delay.