• Journal of Information Processing Systems
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• v.12 no.1
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• pp.73-82
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• 2016

In cognitive radio networks (CRNs), the performance of the transmission control protocol (TCP) at the secondary user (SU) severely drops due to the mistrigger of congestion control. A long disruption is caused by the transmission of primary user, leading to the mistrigger. In this paper, we propose a cross-layer approach, called a CR-aware scheme that enhances TCP performance at the SU. The scheme is a sender side addition to the standard TCP (i.e., TCP-NewReno), and utilizes an explicit cross-layer signal delivered from a physical (or link) layer and the signal gives an indication of detecting the primary transmission (i.e., transmission of the primary user). We evaluated our scheme by implementing it onto a software radio platform, the Universal Software Radio Peripheral (USRP), where many parts of lower layer operations (i.e., operations in a link or physical layer) run as user processes. In our implementation, we ran our CR-aware scheme over IEEE 802.15.4. Furthermore, for the purpose of comparison, we implemented a selective ACK-based local recovery scheme that helps TCP isolate congestive loss from a random loss in a wireless section.

• KEPCO Journal on Electric Power and Energy
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• v.4 no.1
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• pp.1-7
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• 2018

Objective signs are everywhere that the stationary energy storage market is growing up quickly. The use of distributed resources such as solar photovoltaics and electric vehicles are expanding at a rapid pace, creating technical challenges for the distribution system that will require energy storage and a new generation of software to address. This paper is intended for distribution utility managers and executives and makes the following points: ${\bullet}$ Utility-integrated (as opposed to merely grid-connected) energy storage projects represent a distinct, new wave of industry growth that is just getting underway and is required to manage distributed energy resources moving forward. ${\bullet}$ Utilities and the energy storage industry have important roles to lower risk in adopting this technology - thereby enabling this wave of growth. ${\circ}$ The industry must focus on engineering energy storage for adoption at scale - including the creation and support of software open standards -both to drive down costs and to limit technology and supplier risk for utilities. ${\circ}$ Utilities need to take a program-based, rather than a project- based, approach to this resource to best balance cost and risk as they procure and implement energy storage. By working together to drive down costs and manage risk, utilities and their suppliers can lay the energy storage foundation for a new, more digital distributed electricity system.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.603-609
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• 2008

Nowadays, double-system of TFM(Track-side Functional Modules) developed instead of single-system in use of high speed line to acquisition more availability. Safety Law for Railroad recommend to quality certification of development and general railway machines. It is important to select metrics which form the bases for testing software products. A number of package software development part do not open source cords, so testing external characteristic vectors having relationship with metrics. In this paper, review the process for the TFM Point Modules, Universal Modules and Switchers, think about the test methode of circuit boards output performance by using TFM tester and Simulators.

• Annual Conference of KIPS
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• 2012.11a
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• pp.1336-1339
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• 2012

최근 공공기관을 통해 CCTV 영상을 통합관리 하려는 움직임이 활발히 발생하고 있다. 하지만, CCTV의 수가 증가하고, 해상도가 높아지면서 통합관리시 저장비용, 검색비용 등의 문제가 예상되고 있다. 이러한 문제의 해결책으로 클라우드 컴퓨팅 기술을 들 수 있는데, 클라우드 컴퓨팅은 다양한 클라이언트 디바이스에서 필요한 시점에 인터넷을 이용해 공유 풀에 있는 서버, 스토리지, 애플리케이션, 서비스 등과 같은 IT 리소스에 쉽게 접근할 수 있는 것을 가능하게 하는 모델이다. 또한 모바일 클라우드 컴퓨팅은 클라우드 컴퓨팅과 다양한 모바일 기기를 결합하여 다양한 서비스를 제공하는 것이다. CCTV와 같은 영상을 생산하는 클라이언트를 모바일 클라우드의 단말로 보고, 영상 데이터를 클라우드 컴퓨팅을 이용하여 관리하면, 저가의 비용으로 대용량의 영상을 저장하는데 비용을 절감 할 수 있으며, 간단한 방법으로 병렬 처리로 검색을 할 수 있어, 검색 시간을 절감 할 수 있는 효과가 있다. 본 논문에서는 모바일 클라우드를 이용한 범용 영상 통합 관리 시스템 모델을 제안하고 이를 토대로 차량용 블랙박스 분야에 한정한 시스템 설계하고 구현하였다.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.4
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• pp.227-235
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• 1993

In this paper, the development of a high performance flexible controller is described. The hardware of the controller, based on VME-bus, consists of four M68020 single-board computers (32-bit) with M68881 numerical coprocessors, two M68040 single board donputers, I/O devices (such as A/D and D/A converters, paraller I/O, encoder counters), and bus-to-bus adaptor. This software, written in C and based on X-window environment with Unix operating system, includes : text editor, compiler, downloader, and plotter running in a host computer for developing control program ; device drivers, scheduler, and mathemetical routines for the real time control purpose ; message passing, file server, source level debugger virtural terminal, etc. The hardware and software are structured so that the controller might have both flexibility and extensibility. In papallel to the controller, a three degrees of freedom kinematically redundant robot has been developed at the same time. The development of the same time. The development of the robot was undertaken in order to provide, on the one hand, a computationally intensive plant to which to apply the controller, and on the other hand a research tool in the field of kinematically redundant manipulator, which is, as such, an important area. By using the controller, dynamic control of the redundant manipulator was successfully experimented, showing the effectiveness and flexibility of the controller.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.9
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• pp.279-286
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• 2012

Recently, design of Universal Soft Controller(USC) has been applied to the advanced control room for nuclear power plant. USC is software-based manual control means to control safety components as well as non-safety components in the highly-integrated control room. Therefore, design feature of USC is essential for the implementation of a single workstation in the advanced control room. The traditional control room is replaced by computer-driven consolidated operator interfaces. Considering our design has further reduced the probability of USC spurious signals by requiring two distinct operator control actions to generate any control signal. The reality of USC does not increase the probability of reactor trip because the probability of spurious USC signal is negligible. Universal Soft Control represents a significant evolution in nuclear I&C/HSI System. USC integrates the indicators and controls from multiple divisions into a single integrated visual display unit(VDU) based HSI(Human System Interface). In order to prevent adverse influence on safety function performance from USC failure, ESFAS signals are applied to safety components or functions. In addition, safety manual switches have priority over USC's signals. Therefore, spurious USC signals can be momentarily blocked by selecting a soft control command from the safety VDU.

• Radiation Oncology Journal
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• v.20 no.1
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• pp.24-33
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• 2002

Purpose : In order to improve dose homogeneity and to reduce acute toxicity in tangential whole breast radiotherapy, we evaluated two treatment techniques using multiple static fields or universal compensators. Materials and Methods : 1) Multistatic field technique : Using a three dimensional radiation treatment planning system, Adac Pinnacle 4.0, we accomplished a conventional wedged tangential plan. Examining the isodose distributions, a third field which blocked overdose regions was designed and an opposing field was created by using an automatic function of RTPS. Weighting of the beams was tuned until an ideal dose distribution was obtained. Another pair of beams were added when the dose homogeneity was not satisfactory. 2) Universal compensator technique : The breast shapes and sizes were obtained from the CT images of 20 patients who received whole breast radiation therapy at our institution. The data obtained were averaged and a pair of universal physical compensators were designed for the averaged data. DII (Dose Inhomogeneity Index : percentage volume of PTV outside $95\~105\%$ of the prescribed dose) $D_{max}$ (the maximum point dose in the PTV) and isodose distributions for each technique were compared. Results : The multistatic field technique was found to be superior to the conventional technique, reducing the mean value of DII by $14.6\%$ (p value<0.000) and the $D_{max}$ by $4.7\%$ (p value<0.000). The universal compensator was not significantly superior to the conventional technique since it decreased $D_{max}$ by $0.3\%$ (p value=0.867) and reduced DII by $3.7\%$ (p value=0.260). However, it decreased the value of DII by maximum $18\%$ when patients' breast shapes fitted in with the compensator geometry. Conclusion : The multistatic field technique is effective for improving dose homogeneity for whole breast radiation therapy and is applicable to all patients, whereas the use of universal compensators is effective only in patients whose breast shapes fit inwith the universal compensator geometry, and thus has limited applicability.

• Restorative Dentistry and Endodontics
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• v.35 no.2
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• pp.88-95
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• 2010

The purpose of this study was to compare the root canal shaping ability of 4 rotary NiTi instruments in simulated root canals. For the preparation of thirty two curved root canals, Mtwo instruments using "single length"technique, and Profile, ProTaper Universal, and K3 using crown-down technique (N = 8) were used. All canal samples were prepared by reaching an apical canal size of #30. Pre- and post-instrumentation digital images were recorded and an assessment of canal shape was determined using a computer image analysis program SigmaScan Pro (Systat Software Inc., San Jose, CA, USA). The changes of the dimension of inner walls of canals, (2) the changes of the dimension of outer walls of canals, and (3) the centering ratio were measured at 7 measuring points, and then data were statistically analyzed using one-way ANOVA and Duncan's test. The results were as below; 1. The root canal shaping ability of Profile was significantly faster than that of other rotary NiTi instruments (p < 0.05). 2. The deformation and fracture of all instruments used for this study were not experienced. 3. In the degree of changes of the dimension of inner walls of canals, Profile demonstrated the lowest changes of the dimension of inner walls of canals except at the measuring points of the 1 and 2 mm (p < 0.05). However, the ProTaper Universal showed the highest changes of the dimension of inner walls of canals at all measuring points (p < 0.05). 4. In the degree of changes of the dimension of outer walls of canals, Mtwo demonstrated the lowest changse of the dimension of outer walls of canals except at the measuring point of the 1 mm (p < 0.05). However, Profile exhibited the highest changes of the dimension of outer walls of canals at the measuring points of 3 and 4 mm and ProTaper Universal and K3 showed the largest changes of the dimension of outer walls of canals at the measuring points of 1, 2, 6, and 7 mm (p < 0.05). 5. In degree of centering ratio, Profile demonstrated the least centering ratio comparing with the centering ratio shown by other NiTi instruments at the measuring points of 1, 4, 5, and 6 mm. Results suggest that in the coronal part of canal preparation, active cutting files such as ProTaper Universal may efficiently flare the canal orifice and form a better taper, and in the apical part of the canal, files which have a better centering ability such as Profile may maintain the original canal curvature and reduce the shaping time.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.2
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• pp.23-34
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• 2014

Though a dozen of different software life cycle models are suggested, there is no universal model which can satisfy all the characteristics of software. Organizations mix and match different life cycle models to develop a model more tailored for their systems and capabilities. We suggest overlapped-concurrent development life cycle model that is more suitable in various software development environment. Firstly, we divided the development process into abstract and implementation stage. Abstract stage is from software concept phase to detailed design starting time, and implementation stage is from detailed design phase to system testing phase. Next, the abstract stage introduced the overlapped phase concept that begins the next phase when the step is completed 20% by applying pareto's law. In the implementation stage, we introduced the concurrent development which the several phases are performed some time as when one use-case (UC) is completed the next development phase is started immediately. The proposed model has an advantage that it can reduce the inefficiency of development resource greatly. This model can increase the customer satisfaction with a great product at a low cost and on a short schedule. Also, this model can contribute to increase the software development success rate.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.147-156
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• 2011

Though a dozen of different software life cycle models are suggested, there is no universal model which can satisfy all the characteristics of software. Organizations mix and match different life cycle models to develop a model more tailored for their systems and capabilities. We suggest overlapped-concurrent development life cycle model that is more suitable in various software development environment. Firstly, we divided the development process into abstract and implementation stage. Abstract stage is from software concept phase to detailed design starting time, and implementation stage is from detailed design phase to system testing phase. Next, the abstract stage introduced the overlapped phase concept that begins the next phase when the step is completed 20% by applying pareto's law. In the implementation stage, we introduced the concurrent development which the several phases are performed some time as when one use-case (UC) is completed the next development phase is started immediately. The proposed model has an advantage that it can reduce the inefficiency of development resource greatly. This model can increase the customer satisfaction with a great product at a low cost and on a short schedule. Also, this model can contribute to increase the software development success rate.