• Transactions of the Society of Information Storage Systems
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• v.1 no.1
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• pp.1-22
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• 2005

There are two important trends in the modern information society, including digital networking and ubiquitous environment. Thus it is strongly required to develop new information storage devices such as high density storages to match the increased data capacity and small size storage devices to be applied to the mobile multimedia electronics. So far, many approaches have been studied for the high density memory, including the holographic memory, super-RENS and near-field recording using solid immersion lens (SIL) or nano-probe for the ODD (Optical Disk Drive) system, and the perpendicular magnetic recording and heat-assisted magnetic recording for the HDD (Hard Disk Drive) system. In addition, new mobile storage devices have been prepared using 0.85" HDD and 30mm ODD systems from a lot of foreign and domestic companies and institutes. In this paper, the recent technology trend for the next generation information storage system is summarized to offer a research motivation and encouragement to new researchers in this field with an emphasis on the technical issues of the increase of data capacity and decrease of device size.

• The Journal of Information Systems
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• v.15 no.1
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• pp.145-168
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• 2006

Current computer viruses are one of the most serious problems in information age due to their potential demage and impact on use of information systems. To make the problem worse, virus development technology has been advanced rapidly, and use of network systems has expanded widely. Therefore computer viruses are much more complex and use of anti-virus software(AV S/W) is not enough to prrevent virus incidents. It implies that computer viruses as well as other information security matters are not solely a technical problem but also a managerial one. This study emphasized on computer virus controls from managerial perspective of information security and investigated factors influencing the effectiveness of computer virus controls. Organization's comprehensive security policies provide guidelines on how organization or individual can protect themselves from computer viruses. Especially, user's education has positive impact on user's security related characteristics. Based on the analysis of research model using structural equation modeling technique, security policies were influencing security controls and improving user's computer viruses related awareness. Also security controls had positive impact on security effectiveness. However, no significant relationship was found between user's security related characteristics and security effectiveness.

• The Journal of Information Systems
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• v.33 no.3
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• pp.51-74
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• 2024

Purpose This study investigates the key factors influencing knowledge sharing within Online Health Communities (OHCs), focusing on how different types of support impact sharing general health and specific health knowledge. Design/Methodology/Approach This study adopts a quantitative research design, collecting data from 308 participants across various OHCs through a questionnaire survey. The questionnaire assesses the relationships between informational support, emotional support, altruism, personal innovativeness, and knowledge-sharing behavior. Using structural equation modeling (SEM), the researchers systematically analyzed the impact of these factors on the sharing of general health knowledge (such as health advice and lifestyle information) and specific health knowledge (such as medical, technical details, and treatment plans). Findings The analysis revealed that informational support significantly promotes general health and specific health knowledge sharing in OHCs. Emotional support has a notable effect on general health knowledge sharing but is limited in its impact on specific health knowledge sharing, potentially due to the technical nature of the information involved. Altruism positively influences general health knowledge sharing but shows mixed effects on specific health knowledge sharing, possibly due to the complexity and difficulty of the knowledge being shared. Personal innovativeness enhances general health knowledge sharing but may conflict with existing norms in specific health knowledge contexts, leading to variable outcomes.

• The Transactions of the Korea Information Processing Society
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• v.7 no.6
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• pp.1753-1765
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• 2000

As the areas of computer application are expanded, real-time application environments that must process as many transactions as possible within their deadlines, such as a stock transaction systems, ATM switching systems etc, have been increased recently. The reason why the conventional database systems can't process soft real-time applications is the lack of prediction and poor performance on processing transaction's deadline. If transactions want to access data stored at the secondary storage, they can not satisfy requirements of real-time applications because of the disk delay time. This paper designs a main-memory database prototype systems to be suitable to real-time applications and then this system can produce rapid results without disk i/o as all of the information are loaded in main memory database. In thesis proposed the improved techniques with respect to logging, checkpointing, and recovering in our environment. In order to improve the performance of the system, a) the frequency of log analysis and redo processing is reduced by the proposed redo technique at system failure, b) database consistency is maintained by improved fuzzy checkpointing. The performance model is proposed which consists of two parts. The first part evaluates log processing time for recovery and compares with other research activities. The second part examines checkpointing behavior.

• Asia pacific journal of information systems
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• v.22 no.1
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• pp.1-27
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• 2012

Asynchronous Learning Networks (ALN) has become a kind of prevalent information systems to supplement or even substitute a traditional classroom face-to-face teaching method. In this paper, we investigate the impacts of types of courses, lecturers' instruction models and computer self-efficacy on the ALN effectiveness in teaching from lecturers' perspective. We conducted survey to professors in various faculties such as School of Computing, Faculty of Arts, Science, Business, Law and Engineering in the National University of Singapore. According to the responses from ninety-eight professors, instruction modes positively influence the usage of ALN; types of course and lecturers' computer-efficacy influence lectures' satisfaction of ALN in teaching. Both the usage of ALN and satisfaction of ALN positively influence the effectiveness of ALN. The results of this study fill the gap of ALN researches in education by examining it from lecturers' perspective and enable schools to improve their implementation of ALN systems based on our findings.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.73-76
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• 2006

Pilots and navigators have through history used everything available to support them in the execution of their task. From the simple sounding means (for instance a stick or a line with a heavy object tied to it) to the advanced electronic support systems that are available today. This means that apart from the more traditional side of his set of tasks the influence of modern technology is felt. In general it concerns such diverse and complex subjects that it requires the pilot to remain up to date with regard to the most modern techniques. In a sense this also concurs with the change form a provider of (local) knowledge to that of a manager of a high risk operation. More information flows can reach the pilot on the place where he executes his profession. With marginal scope the pilot has to translate such information to the situation in which he finds himself in order to give a balanced advice. Knowledge of the surroundings, variable circumstances in his specific area but also language and culture play a crucial role. This paper touches on the history of pilot support systems and examines the developments of pilot support systems in the present day operating environment and addresses the implications. These range from the historic basic needs for pilot information to the present and future possibilities, supporting the pilot to make the most precise assessment at each operational stage to continually execute a safe journey in and out of port.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.08a
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• pp.173-181
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• 2000

Lockheed Martin has integrated and installed numerous AIS systems around the world as part of several VTS installation contracts and technology demonstrations for customers. Each of these systems incorporates specific customer requirements addressing differing objectives. This paper describes the capabilities and features of Lockheed Martin's current implementation of the Universal AIS system, and the experiences Lockheed Martin has had with earlier AIS and ADS (automated dependent surveillance) system installations. Specific examples are provided for an amphibious landing exercise with the US Army; installations at a Middle-East Oil port; technology demonstrations in New York Harbor, USA; river systems in New Orleans, Louisiana, USA; and coastal applications in the Gulf of Suez. The paper closes a brief overview of the most recent activity, the Turkish Straits VTMIS project that requires Universal AIS installations. The evolution of the technology and lessons learned will be discussed in the context of these examples. The perspective will be on Lockheed Martin's experience working with different customers to integrate AIS technology into a larger VTS or Port Information System. It will also discuss, from the practical side, how AIS information is used by a variety of maritime organizations with differing needs and information objectives.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.8
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• pp.4160-4173
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• 2019

Borescopes facilitate the inspection of areas inside machines and systems that are not directly accessible for visual inspection. They offer real-time, up-close access to confined and hard-to-access spaces without having to dismantle or destructure the object under inspection. Borescopes are ideal instruments for routine maintenance, quality inspection and monitoring of systems and structures. The main application being fault or defect detection, it is useful to have measuring capability to quantify object dimensions in a target area. High-end borescopes use multi-optic solutions to provide measurement information of viewed objects. Multi-optic solutions can provide accurate measurements at the expense of structural complexity and cost increase. Measuring functionality is often unavailable in low-end, single camera borescopes. In this paper, a single camera measurement solution that enables the size estimation of viewed objects is proposed. The proposed solution computes and overlays a scaled grid of known spacing value over the screen view, enabling the human inspector to estimate the size of the objects in view. The proposed method provides a simple means of measurement that is applicable to low-end borescopes with no built-in measurement capability.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.6
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• pp.2908-2924
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• 2019

Multiple input multiple output orthogonal frequency division multiplexing (MIMO-OFDM) is widely applied in wireless communication by virtue of its excellent properties in data transmission rate and transmission accuracy. However, as a major drawback of MIMO-OFDM systems, the high peak-to-average power ratio (PAPR) complicates the design of the power amplifier at the receiver end. Some available PAPR reduction methods such as selective mapping (SLM) suffer from high computational complexity. In this paper, a low-complexity SLM method based on active constellation extension (ACE) and joint space-time selective mapping (AST-SLM) for reducing PAPR in Alamouti STBC MIMO-OFDM systems is proposed. In SLM scheme, two IFFT operations are required for obtaining each transmission sequence pair, and the selected phase vector is transmitted as side information(SI). However, in the proposed AST-SLM method, only a few IFFT operations are required for generating all the transmission sequence pairs. The complexity of AST-SLM is at least 86% less than SLM. In addition, the SI needed in AST-SLM is at least 92.1% less than SLM by using the presented blind detection scheme to estimate SI. We show, analytically and with simulations, that AST-SLM can achieve significant performance of PAPR reduction and close performance of bit error rate (BER) compared to SLM scheme.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.5898-5916
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• 2018

In this paper, the downlink performance of multi-cell distributed antenna systems (DAS) with a single user in each cell is investigated. Assuming the channel state information is available at the transmitter, four transmission modes are formulated as combinations of remote antenna units (RAUs) selection and cooperative transmission, namely, non-cooperative transmission without RAU selection (NCT), cooperative transmission without RAU selection (CT), non-cooperative transmission with RAU selection (NCT_RAUS), and cooperative transmission with RAU selection (CT_RAUS). By using probability theory, the cumulative distribution function (CDF) of a user's signal to interference plus noise ratio (SINR) and the system ergodic capacity under the above four modes are determined, and their closed-form expressions are obtained. Furthermore, the system energy efficiency (EE) is studied by introducing a realistic power consumption model of DAS. An expression for determining EE is formulated, and the closed-form tradeoff relationship between spectral efficiency (SE) and EE is derived as well. Simulation results demonstrate their consistency with the theoretical analysis and reveal the factors constraining system EE, which provide a scientific basis for future design and optimization of DAS.