• Journal of Korean Academy of Nursing
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• v.35 no.7
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• pp.1229-1237
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• 2005

Purpose: The purpose of this research was to address the working conditions of home health nurses through a nationwide home health agency survey conducted at hospitals. Method: The mail surveys were sent to 303 home health nurses nation wide and returned with a response rate of $71.8\%$. Result: (a) Seventy-five percent of home health agencies were established within the past5 years and half of home health nurses are over 40 years old. (b) Working conditions were considered as follows: Seventy-one percent of respondents were full-time employees, sixty-sixpercent of home health nurses had unscheduled visits on a regular day of duty and forty-eight percent were on vacation. Fifty-one percent of home health nurses have experienced traffic accidents and paid. penalties ($65.9\%$). Self-reported monthly income level per year was an average of 28,364,000 won. (c) Rates were significantly higher for shoulder pain ($61.5\%$), lower back pain ($54.1\%$), knee pain ($39.4\%$), and gastrointestinal problems ($33.0\%$). Conclusion: These baseline results show the importance of improving home health nursing working conditions, a comprehensive prevention system and safeguards from physical discomfort.

• The Journal of the Convergence on Culture Technology
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• v.6 no.1
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• pp.495-500
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• 2020

VANET (Vehicular Ad Hoc Network), an example of an ad hoc vehicular networks, becomes one of the popular research areas together with the self-driving cars and the connected cars. In terms of the VANET implementation, the traditional TCP/IP protocol stack could be applied to VANET. Recently, CCN (Content Centric Networking) shows better possibility to apply to VANET, called VCCN (VANET over CCN). CCN maintains several data tables including CS (Content Store) which keeps track of the currently requested content segments. When the CS becomes full and new content should be stored in CS, a replacement algorithm is needed. This paper compares and contrasts four replacement algorithms. In addition, it analyzes the transmission characteristics in diverse network conditions. According to the simulation results, LRU replacement algorithm shows better performances than the remaining three algorithms. In addition, even the size of CS is small, the network maintains a reasonable transmission performance. As the CS size becomes larger, the transmission rate increases proportionally. The transmission performance decreases when the network is crowded as well as the number of transmission hops becomes large.

• International Journal of Internet, Broadcasting and Communication
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• v.10 no.3
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• pp.26-34
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• 2018

In this paper, we propose a scheduling scheme that can efficiently serve I/O requests having deadlines in flash storage. The I/O requests with deadlines, namely, real-time requests, are assumed to be issued for streaming services of continuous media. Since a Web-based streaming server commonly supports downloads of HTMLs or images, we also aim to quickly process non-real-time I/O requests, together with real-time ones. For this purpose, we adopt the well-known rate-reservation EDF (RR-EDF) algorithm for determining scheduling priorities among mixed I/O requests. In fact, for the use of an EDF-style algorithm, overhead of task's switching should be low and predictable, as with its application of CPU scheduling. In other words, the EDF algorithm is inherently unsuitable for scheduling I/O requests in HDD storage because of highly varying latency times of HDD. Unlike HDD, time for reading a block in flash storage is almost uniform with respect to its physical location. This is because flash storage has no mechanical component, differently from HDD. By capitalizing on this uniform block read time, we compute bandwidth utilization rates of real-time requests from streams. Then, the RR-EDF algorithm is applied for determining how much storage bandwidth can be assigned to non-real-time requests, while meeting deadlines of real-time requests. From this, we can improve the service times of non-real-time requests, which are issued for downloads of static files. Because the proposed scheme can expand flexibly the scheduling periods of streams, it can provide a full usage of slack times, thereby improving the overall throughput of flash storage significantly.

• Smart Structures and Systems
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• v.17 no.1
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• pp.91-105
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• 2016

One of the most commonly used techniques to strengthen steel reinforced concrete structures is the application of externally bonded patches in the form of carbon fiber reinforced polymers (CFRP) or recently, textile reinforced cements (TRC). These external patches undertake the tensile stress of bending constraining concrete cracking. Development of full-field inspection methodologies for fracture monitoring are important since the reinforcing layers are not transparent, hindering visual observation of the material condition underneath. In the present study acoustic emission (AE) and digital image correlation (DIC) are applied during four-point bending tests of large beams to follow the damage accumulation. AE helps to determine the onset of fracture as well as the different damage mechanisms through the registered shifts in AE rate, location of active sources and change in waveform parameters. The effect of wave propagation distance, which in large components and in-situ can well mask the original information as emitted by the fracture incidents is also discussed. Simultaneously, crucial information is supplied by DIC concerning the moments of stress release of the patches due to debonding, benchmarking the trends monitored by AE. From the point of view of mechanics, conclusions on the reinforcing contribution of the different repair methodologies are also drawn.

• Macromolecular Research
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• v.11 no.5
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• pp.368-374
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• 2003

Porous scaffolds composed of gelatin and polysaccharides such as hyaluronic acid and $\beta$-glucan were prepared by using the freeze-drying method after cross-linking with l-ethyl-(3-3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). The scaffold had an inter-connected pore structure with the sufficient pore size for use as a support for the growth of fibroblasts. Results for the contact angle and cell attachment confirmed that high gelatin content in a mixture was suitable for cellular attachment and distribution in two- or three-dimensional fibroblast cultures. However, the addition of polysaccharides aroused the synergistic effects of morphologic and mechanical property of gelatin-based scaffolds. To prepare the artificial dermis for the wound dressing to mimic the normal human dermal skin, fibroblasts were isolated from a child's foreskin, and cultured in gelatin-based scaffolds. An in vivo study showed that the artificial dermis containing the fibroblasts enhanced the wound healing rate and re-epithelialization of a full-thickness skin defect rather than the acellular scaffold after one week.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.2
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• pp.273-284
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• 2015

The feasibility conditions of interference alignment (IA) are analyzed for reverse duplex systems, in which one cell operates as downlink (DL) while the other cell operates as uplink (UL) assuming one-sid base station (BS) cooperation. Under general multiple-input and multiple-output (MIMO) antenna configurations, a necessary condition and a sufficient condition for one-shot linear IA are established, i.e., linear IA without symbol or time extension. In several example networks, optimal sum degrees of freedom (DoF) is characterized by the derived necessary condition and sufficient condition. For some special class of networks, a sufficient condition is established in a more compact expression, which also yields the necessary and sufficient condition. Simulation results demonstrate that the proposed IA does not only achieve larger DoF but also significantly improves the sum rate in the practical signal-to-noise ratio (SNR) regime.

• Journal of Information Technology Services
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• v.14 no.3
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• pp.183-196
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• 2015

The concept of energy-efficient networking has begun to spread in the past few years, gaining increasing popularity. A common opinion among networking researchers is that the sole introduction of low consumption silicon technologies may not be enough to effectively curb energy requirements. Thus, for disruptively boosting the network energy efficiency, these hardware enhancements must be integrated with ad-hoc mechanisms that explicitly manage energy saving, by exploiting network-specific features. The IEEE 802.3az Energy Efficient Ethernet (EEE) standard is one of such efforts. EEE introduces a low power mode for the most common Ethernet physical layer standards and is expected to provide large energy savings. However, it has been shown that EEE may not achieve good energy efficiency because mode transition overheads can be significant, leading to almost full energy consumption even at low utilization levels. Coalescing techniques such as packet coalescing and interrupt coalescing were proposed to improve energy efficiency of EEE, but their implementations typically adopt a simple policy that employs a few fixed values for coalescing parameters, thus it is difficult to achieve optimal energy efficiency. The paper proposes adaptive interrupt coalescing (AIC) that adopts an optimal policy that could not only improve energy efficiency but support performance. AIC has been implemented at the sender side with the Intel 82579 network interface card (NIC) and e1000e Linux device driver. The experiments were performed at 100 M bps transfer rate and show that energy efficiency of AIC is improved in most cases despite performance consideration and in the best case can be improved up to 37% compared to that of conventional interrupt coalescing techniques.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.8
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• pp.1774-1781
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• 1997

In this paper, we propose a full digital frequency and phase locked loop for CATV and HDTV receivers adopting VSB modulation. The CATV and HDTV receivers proposed by the Grand-Alliance in USA are ultilizing analog signal processing technology for carrier recovery. By the way, it is not a good architecture for the development of single chip ASIC operating in digital domain. To solve this problem while improving the performance, we first down convert the received r.f. signal to a near baseband signal for a low-rate AD converter and then we use digital signal processing techniques. The proposed system has the frequency pull-in range of -200 KHz +2.50 KHz. Moreover, it has the ability of adaptive loop bandwidth control according to the amount of frequency offset to improve the acquisition time while reducing the phase noise.

• Journal of the Korean association of regional geographers
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• v.7 no.2
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• pp.1-16
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• 2001

This paper is to examine the trends and structures of unemployment as well as its spatial patterns in Germany. Germany once achieved a well-developed employment system and full employment. Since 1970, however, unemployment has been one of the major issues in Germany. During the last three decades the unemployment rate has risen to unprecedented levels and stayed high. After the German unification, especially, labor market is characterized by the mass unemployment and the structural selective process of unemployment to be imposed on German workers. And regarding to the spatial patterns of massive unemployment, this study shows critical disparities between South and North Germany being overlapped with new disparities between East and West Germany. We can explain the regional differentiation of unemployment on the base of typical mismatch of labour market allocation. It is also shown that massive unemployment is related not only to policy shifts in labor market but also to structural transformation after the unification.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.1
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• pp.133-140
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• 2012

The study of Arundinaria munsuensis Y. Lee to this day was limited to the field of morphological species classification since its first discovery at Jiri mountain in the late 1990s. This native plants, one of Korean endemic species found in Jiri Mt. necessitates further studies about its use as revegetation plants or groundcover plants in urban areas. This study was launched from this need followed by summaries of results below related to its usage. This targeted species is a native Korean species which its natural distribution on the subalpine zone has merit for the wide range of climatic adaptation. Also, the coverage rate reached 78.3% in three years mostly by rhizome growth with an expectation of full coverage in four years providing less maintenance needs after planting. The net price for the construction of pot seedling methods of this plants is relatively economical than other normal revegetation construction methods. For these reasons, drilling for the plants on cut and fill soil slopes driven from pot seedling adapts Arundinaria munsuensis Y. Lee as efficient revegetation plant. Total construction cost for pot seedling work($30cm{\times}30cm$) of Arundinaria munsuensis was approximately 21,000won which is in reasonable price range when compared to other revegetation construction methods of disturbed slopes. As a native Korean plant, Arundinaria munsuensis has wide range of climatic adaptation with less maintenance requirement after planting. This study may suggest a strong possibility of Arundinaria munsuensis as a pot planting material in sloped area.