• Journal of the Institute of Convergence Signal Processing
• /
• v.15 no.2
• /
• pp.64-69
• /
• 2014

Ultrasound system is one of the complex wireless signal processing systems that are widely used in the fields of modern industry such as medical diagnostics, underwater communications, and sensor-networks. Miniaturization of ultrasound system has been raging recently. In this paper, a hybrid LNA that is suitable for miniaturization and mobile diagnostic ultrasound system has been developed. The proposed LNA has low noise figure of less than 5dB, and the feedback resistor is designed to be electrically adjusted in order to attain the impedance-matching for various ultrasound transducers. It supports the whole ultrasound frequencies from 10KHz to 150MHz frequency band and also provides sleep modes. A gain from -18.8 to -29.5 dB is achieved by adjusting each transducer to fit the system character. Power consumption can be reduced up to 90% in similar performance as compared to the existing LNA.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.8 no.4
• /
• pp.1208-1222
• /
• 2014

Due to the low utilization and scarcity of frequency spectrum in current spectrum allocation methodology, cognitive radio networks (CRNs) have been proposed as a promising method to solve the problem, of which spectrum sensing is an important technology to utilize the precious spectrum resources. In order to protect the primary user from being interfered, most of the related works focus only on the restriction of the missed detection probability, which may causes over-protection of the primary user. Thus the interference probability is defined and the interference-aware sensing model is introduced in this paper. The interference-aware sensing model takes the spatial conditions into consideration, and can further improve the network performance with good spectrum reuse opportunity. Meanwhile, as so many fading factors affect the spectrum channel, errors are inevitably exist in the reporting channel in cooperative sensing, which is improper to be ignored. Motivated by the above, in this paper, we study the throughput tradeoff for interference-aware cognitive radio networks over imperfect reporting channel. For the cooperative spectrum sensing, the K-out-of-N fusion rule is used. By jointly optimizing the sensing time and the parameter K value, the maximum throughput can be achieved. Theoretical analysis is given to prove the feasibility of the optimization and computer simulations also shows that the maximum throughput can be achieved when the sensing time and the parameter of K value are both optimized.

• Journal of Korea Spatial Information System Society
• /
• v.3 no.1 s.5
• /
• pp.37-48
• /
• 2001

ITS includes an Advanced Traveler Information System(ATIS) that provides travelers with service and facility data for the purpose of assisting prior to embarking on a trip or after the traveler is underway. ATIS consists of three major subsystems, which are a Pre-trip Traffic Information subsystem(PTIS), an En-route Traffic Information Subsystem(ETIS), and a Dynamic Route Guide Subsystem(DGIS). ATIS needs to be designed and implemented in accordance with the National ITS Architecture, a reference framework that spans all of standards activities. Recently, as software technology is rapidly improved and stabilized, there are some needs to reuse pre-developed and powerful ITS technology. ITS standardization based on components and open interfaces becomes a way to solve these reusability of current ITS technology. This paper focuses on how could we design and implement ATIS based on the component with the aid of UML(Unified Modeling Language). The UML methodology is expected to provide a standardized model for newly developed ITS components.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.2C
• /
• pp.333-341
• /
• 2004

Along with the innovative enhancement of Internet technology and the emergency of distributed systems extended from client-server computing, it becomes indispensible and necessary to integrate and interconnect old legacy systems. Since building a distributed system requires consistency of integration, the proper reuse of incumbent systems is critical to successful integration of current systems to distributed ones. CORBA(Common Object Request Broker Architecture) and object wrapping technique can provide middleware solutions that extend the applications of a legacy system with little modification to the application level while keeping client consistency of standard interface. By using these techniques for system integration it is easier and faster to extend services on application development to distributed environments. We propose a model on object wrapping system that can manage, integrate, and separate the functions delivered from CORBA. We apply the object wrapping model specifically to integration of security system interfaces and also perform a test to verify the usability and the efficiency of our model.

• Nuclear Engineering and Technology
• /
• v.45 no.1
• /
• pp.29-40
• /
• 2013

Two different kinds of nuclear power plants produce a substantial amount of spent fuel annually in Korea. According to the current projection, it is expected that around 60,000 MtU of spent fuel will be produced from 36 PWR and APR reactors and 4 CANDU reactors by the end of 2089. In 2006, KAERI proposed a conceptual design of a geological disposal system (called KRS, Korean Reference disposal System for spent fuel) for PWR and CANDU spent fuel, as a product of a 4-year research project from 2003 to 2006. The major result of the research was that it was feasible to construct a direct disposal system for 20,000 MtU of PWR spent fuels and 16,000 MtU of CANDU spent fuel in the Korean peninsula. Recently, KAERI and MEST launched a project to develop an advanced fuel cycle based on the pyroprocessing of PWR spent fuel to reduce the amount of HLW and reuse the valuable fissile material in PWR spent fuel. Thus, KAERI has developed a geological disposal system for high-level waste from the pyroprocessing of PWR spent fuel since 2007. However, since no decision was made for the CANDU spent fuel, KAERI improved the disposal density of KRS by introducing several improved concepts for the disposal canister. In this paper, the geological disposal systems developed so far are briefly outlined. The amount and characteristics of spent fuel and HLW, 4 kinds of disposal canisters, the characteristics of a buffer with domestic Ca-bentonite, and the results of a thermal design of deposition holes and disposal tunnels are described. The different disposal systems are compared in terms of their disposal density.

• The Journal of Korean Association of Computer Education
• /
• v.12 no.5
• /
• pp.35-47
• /
• 2009

Just as noted in some studies related to U-learning based on the ubiquitous technology, it is required to reflect both factors of the environments and contexts of learners on the teaching and learning strategy. For this, the current paper suggests an inquiry learning method and a mobile learning support device for the inquiry learning. Since the inquiry learning is operating on the basis of the contents that learners themselves experience in the fields, it naturally leads them to position in the learning environments and contexts. In this study some curricula are adopted and transformed for the inquiry learning, and the developed mobile device for the learning has a guide function, so that learners might follow the inquiry learning process. In addition, it is possible to reuse the acquired learning data by storing them on a remote learning sever, which may support the inquiry learning of students. These system and device are applied in the teaching sites of schools and, consequently, it is found that in regard with the learning interest and academic performance of students there is an advanced result, being statistically significant.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.11 no.4
• /
• pp.229-237
• /
• 2011

In this paper, a 60 GHz LTCC SiP with low-power CMOS OOK modulator and demodulator is presented. The 60 GHz modulator is designed in a 90-nm CMOS process. The modulator uses a current reuse technique and only consumes 14.4-mW of DC power in the on-state. The measured data rate is up to 2 Gb/s. The 60 GHz OOK demodulator is designed in a 130nm CMOS process. The demodulator consists of a gain boosting detector and a baseband amplifier, and it recovers up to 5 Gb/s while consuming low DC power of 14.7 mW. The fabricated 60 GHz modulator and demodulator are fully integrated in an LTCC SiP with 1 by 2 patch antenna. With the LTCC SiP, 648 Mb/s wireless video transmission was successfully demonstrated at wireless distance of 20-cm.

• The Journal of Society for e-Business Studies
• /
• v.10 no.4
• /
• pp.1-18
• /
• 2005

In ebXML, a representative framework for electronic commerce, a BPS (Business Process Specification) should be finally defined as an instance of XML-version BPSS for the configuration of B2B (Business to Business) runtime systems . In order to define the instance more complete and consistent, it is required to validate all the semantic constraints on the instance . Due to the limitations of XML Schema constructs, however, current XML-version BPSS fails to specify formal semantic constraints completely. This paper presents how to find, express and reuse BPSS semantic constraints that could not be explicitly defined in the XML-version BPSS. The method facilitates the validation of XML-version BPSS instances easily with some useful guides for fixing violations of semantic constraints. Furthermore, B2B business processes can be standardized and applied more efficiently and effectively.

• The KIPS Transactions:PartC
• /
• v.16C no.1
• /
• pp.1-12
• /
• 2009

Today, Digital Right Management (DRM) is used to protect copyrights of digital contents from illegal reproduction and redistribution. Unfortunately, current DRM systems are causing user's discomfort because of lack of mutual compatibility. In order to overcome this drawback, technologies for interoperability of heterogeneous DRM systems are developing. In this paper, we study the protection profile for conversion technologies of heterogeneous DRM systems, using the Common Criteria. Especially, this paper is written by reuse of the existing protection profile. Therefore, performance analysis reveals that efficiency of time and cost is significantly improved. This protection profile can be used by contents provider and administrator who manage user's copyrights to reference data for copyright protection.

• Journal of Korea Port Economic Association
• /
• v.25 no.4
• /
• pp.251-280
• /
• 2009

The value of Environment is so high and important that no one can estimate it correctly. In the area of Logistics, Environment protection is very important and keen subject for the present and for the future of this country and people. Environmental logistics, similarly used as Green logistics, means the protection of Nature and Environment and reduces all kinds of factors and behaviors that may destroy and deteriorate current Environment. It also include the preservation of Nature and sustainable development. Environmental logistics aims to save natural resources and to promote reuse of all kinds of materials and to increase the utilization of Environment friendly substitute goods. In this paper the concept and characteristics of Environmental logistics were summarized and described. Also the main previous studies were surveyed. Some of important cases and experiences which were introduced and applied in major countries such as Japan, Hongkong, USA and the case of PHILIPS were summarized and analyzed. With these cases and analysis, this paper suggested some alternatives and countermeasures for the improvement of Environmental logistics in terms of 3 dimensions such as Country, Company and Individual level. And a strategy model for enhancement of the Environmental logistics was suggested and limitations of this paper and future research directions were described.