• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.459-463
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• 2001

We model and simulate master-driven TDD wireless communication systems, e.g., Bluetooth systems. We model the Bluetooth system and use the BONeS simulation tool to conduct event-drivers simulations. In order to support more than seven slave devices in a piconet, a park mode is considered and modeled. We evaluate the performance, i.e., throughput and delay, using simulations when multi-connections (bath ACL and SCO connections) are present in a piconet. We show that the data rate of ACL connections may be less than 20 kbps when SCO connection(s) and more than six ACL connections are jointly supported in a piconet. In addition, if up to five ACL connections are supported, the average delay is shown to be maintained less than 20 msec. Our results can serve as a guideline to the design of master-driven TDD wireless communication systems with performance requirements.

• Journal of Families and Better Life
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• v.31 no.1
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• pp.73-84
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• 2013

The purpose of this study is to examine the variables influencing marital satisfaction of newly married men and women who have been married for 5 years and do not have a child yet. Data were collected from 242 newly married men and women who were living in Busan. Major findings were as follows : First, newly married men were more satisfied with their marriage when they engage in frequent pleasure seeking activities, had high intimacy with parent of both families and had less communication behavior escalating marital conflict. Second, newly married women were more satisfied with their marriage when they engage in frequent pleasure seeking activities, had high intimacy with parent of both families, had mild depression, and had less communication behavior escalating marital conflict.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.1
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• pp.97-101
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• 2013

There is a growing need for optical communication systems that convert large volumes of data to optical signals and that accommodate and transmit the signals across long distances. Digital optical communication consists of a master unit (MU) and a slave unit (SU). The MU transmits data to SU using digital optical signals. However, digital optical units that are commercially available or are under development transmit data using two's complement representation. At low input levels, a large number of SSOs (simultaneous switching outputs) are required because of the high rate of bit switching in two's complement, which thereby increases the power noise. This problem reduces the overall system capability because a DSP (digital signal processor) chip (FPGA, CPLD, etc.) cannot be used efficiently and power noise increases. This paper proposes a change from two's complement to a more efficient method that produces less SSO noise and can be applied to existing digital optical units.

• Journal of Technology Innovation
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• v.13 no.3
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• pp.1-25
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• 2005

This Paper examines the effect of IT knowledge and IT communication on the operational performance of small firms. Small firms which could be defined firms with less than 50 people in total lags behind medium and large firms in computerization. In order to fill up the computerization gap resulted from size differences, Korean government has been promoting the 'Networking Small Firms' project since 2001. Survey data with 698 small firms in Korea, we could find that If knowledge and IT communication significantly contributed to the operational performance of small firms. Internal process performance is affected by individual IT knowledge, traditional communication, and e-mail communication. Customer performance is affected by above three factors, organizational IT knowledge and internet/EDI communication. Interestingly, financial performance is not affected by traditional communication but only IT knowledge and IT communication.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.4
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• pp.1396-1414
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• 2018

With the proliferation of the Internet of Things (IoT) healthcare devices, significant interoperability issue arises where devices use proprietary data transfer protocols. The IHE PCD-01 standard has been suggested for the exchange of healthcare data in ISO/IEEE 11073 PHD data model. However, the PCD-01 is not efficient to be used in the IoT environment. This is because the use of SOAP for PCD-01 may be too complex to be implemented in the resource-constrained IoT healthcare devices. In this paper, we have designed a communication system to implement ISO/IEEE 11073 and IHE PCD-01 integration using the IETF CoAP. More specifically, we have designed the architecture and procedures, using CoAP, to seamlessly transmit the bio-signal from the tiny resource-constrained IoT healthcare devices to the server in a standardized way. We have also built the agent, gateway, and PCD-01 interface at the server, all of which are using the CoAP as a communication protocol. In order to evaluate the performance of the proposed system, we have used the PCD data to be transmitted over CoAP, MQTT, and HTTP. The evaluation of the system performance shows that the use of CoAP results in faster transaction and lesser cost than other protocols, with less battery power consumption.

• Transactions of the Society of Information Storage Systems
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• v.3 no.2
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• pp.94-112
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• 2007

Nano-sized inverted domain dots in ferroelectric materials have potential application in ultrahigh-density rewritable data storage systems. Herein, a data storage system is presented based on scanning non-linear dielectric microscopy and a thin film of ferroelectric single-crystal lithium tantalite. Through domain engineering, we succeeded to form an smallest artificial nano-domain single dot of 5.1 nm in diameter and artificial nano-domain dot-array with a memory density of 10.1 Tbit/$inch^2$ and a bit spacing of 8.0 nm, representing the highest memory density for rewritable data storage reported to date. Sub-nanosecond (500psec) domain switching speed also has been achieved. Next, long term retention characteristic of data with inverted domain dots is investigated by conducting heat treatment test. Obtained life time of inverted dot with the radius of 50nm was 16.9 years at $80^{\circ}C$. Finally, actual information storage with low bit error and high memory density was performed. A bit error ratio of less than $1\times10^{-4}$ was achieved at an areal density of 258 Gbit/inch2. Moreover, actual information storage is demonstrated at a density of 1 Tbit/$inch^2$.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.9
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• pp.3348-3364
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• 2021

Magic matrix-based data hiding schemes are applied to transmit secret information through open communication channels safely. With the development of various magic matrices, some higher dimensional magic matrices are proposed for improving the security level. However, with the limitation of computing resource and the requirement of real time processing, these higher dimensional magic matrix-based methods are not advantageous. Hence, a kind of data hiding scheme based on a single or a group of multi-dimensional flexible magic matrices is proposed in this paper, whose magic matrix can be expanded to higher dimensional ones with less computing resource. Furthermore, an adaptive mechanism is proposed to reduce the embedding distortion. Adapting to the secret data, the magic matrix with least distortion is chosen to embed the data and a marker bit is exploited to record the choice. Experimental results confirm that the proposed scheme hides data with high security and a better visual quality.

• Journal of Preventive Medicine and Public Health
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• v.55 no.4
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• pp.342-350
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• 2022

Objectives: Human immunodeficiency virus (HIV) prevention among youth seems under-prioritised compared to other key populations. HIV knowledge and stigma are important parts of HIV prevention. To inform HIV prevention among youths, this study quantitatively analysed the associations between open communication regarding sexuality and sexual health, comprehensive HIV knowledge, and non-stigmatising attitudes in Indonesia. Methods: This study used data from the Indonesian Demographic and Health Survey (IDHS) 2017. The analysis included unmarried men and women aged 15-25 years old. Comprehensive HIV knowledge and a stigmatising attitude were defined according to the IDHS 2017. Open communication about sexuality and sexual health was defined as the number of people with whom participants could openly discuss these topics in their direct network of friends, family, and service providers, with a scale ranging from 0 to a maximum of 7. Primary analysis used binomial logistic regression with weighting adjustments. Results: The final analysis included 22 864 respondents. Twenty-two percent of youth had no one in their direct network with whom to openly discuss sexual matters, only 14.1% had comprehensive HIV knowledge, and 85.9% showed stigmatising attitudes. Youth mostly discussed sex with their friends (55.2%), and were less likely to discuss it with family members, showing a predominant pattern of peer-to-peer communication. Multivariate analysis showed that having a larger network for communication about sexuality and sexual health was associated with more HIV knowledge and less stigmatising attitudes. Conclusions: Having more opportunities for open sex communication in one's direct social network is associated with more HIV knowledge and less stigmatising attitudes.

• Journal of Korean Clinical Nursing Research
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• v.29 no.3
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• pp.238-248
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• 2023

Purpose: This study aimed to examine the relationships between positive nursing organizational culture, organizational communication satisfaction, and the level of work engagement among nurses working in tertiary hospitals, as well as to identify influencing factors on work engagement. Methods: This study used a descriptive research design. Data were collected from 184 general nurses working in four tertiary hospitals in Seoul using self-report questionnaires from March 13 to 30, 2023. The collected data were analyzed using descriptive statistics, t-test, ANOVA, Scheffé test, Pearson correlation, and hierarchical regression. Results: In the hierarchical regression analysis, the variables that significantly influenced work engagement in Model 1 were marital status (β=.26, p=.002), graduate or higher degree (β=.41, p<.001), more than 1 year and less than 3 years (β=.18, p=.030) and 3 years or more but less than 5 years of clinical experience in present hospital (β=.17, p=.023), and satisfaction (β=.27, p=.002) and moderate satisfaction with pay (β=.18, p=.033). In model 2, adding the subdomains of positive nursing organizational culture and organizational communication satisfaction to the Model 1, the variables that had a significant effect on work engagement were trust-based organizational relationships (β=.50, p<.001) and organizational communication satisfaction (β=.25, p=.005). Conclusion: The results suggest that education level, clinical experience, and satisfaction with pay should be considered to improve nurses' work engagement. In addition, it was identified that organizational relationship based on trust and organizational communication satisfaction are the main influencing factors for improving work engagement.

• IEIE Transactions on Smart Processing and Computing
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• v.2 no.5
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• pp.282-296
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• 2013

With the emergence of cloud computing, more and more sensitive user data are outsourced to remote storage servers. The privacy of users' access pattern to the data should be protected to prevent un-trusted storage servers from inferring users' private information or launching stealthy attacks. Meanwhile, the privacy protection schemes should be efficient as cloud users often use thin client devices to access the data. In this paper, we propose a lightweight scheme to protect the privacy of data access pattern. Comparing with existing state-of-the-art solutions, our scheme incurs less communication and computational overhead, requires significantly less storage space at the user side, while consuming similar storage space at the server. Rigorous proofs and extensive evaluations have been conducted to show that the proposed scheme can hide the data access pattern effectively in the long run after a reasonable number of accesses have been made.