Catálogo de publicaciones - libros

In mobile usage scenarios, patient care involving point of care considerations build upon increasingly complex information and information structures. Furthermore, communication of information must be enabled regardless of space and time. Decision support and guidelines are expected to communicate with other subsystems, such as those provided by information sources and hardware devices. As also these subsystems may build upon intelligence and involve their own usage scenarios, this implies further complications also the knowledge representation and software engineering tasks. In these developments, public health problems provide case studies with potentially rather huge impacts. Examples are provided e.g. by guidelines involving pharmacological treatment. Knowledge and reasoning need to interact with information management, and often involves utility of various devices. Well organized databases for pharmacological information are necessary for successful engineering of mobile extensions in these case studies. The public is now also one of the driving forces in these developments. As electronic prescriptions and generic substitutes are appreciated by the public, we experience how knowledge in its various forms provide success stories in this field.

This paper concerns a wireless control system (WCS) for pet dogs using wireless sensor networks (WSNs) in a residential environment. The developed WCS is composed of a central control system, a wireless auto-feeder, a small-sized guidance robot, and wireless sensing devices. The developed system uses luminance, temperature, and sound data from a pet dog and the surrounding environment. The presented design method provides an efficient way to control and monitor the pet dog using WSNs. The implemented system can be used as a design framework of portable devices for pet dog control within a residential network.

This paper presents an intelligent embedded, modular software and hardware architecture for multi-shaped robots using real-time dynamic skill identification and selection. It is a layered architecture with reusable and reconfigurable modules, which can embed in an expert system as both hardware and software modules and demonstrated with snake robot and physically reconfigured four-legged robot as examples. The intelligent dynamic selection and synchronization of selected behaviors enable the mobile robot to perform many tasks in complex situations. The architecture proposed is applicable to multi-shaped robots, for dynamic selection of behaviors during reconfiguration, where the hardware and software modules can be reused during reconfiguration. Related videos of these robots can be viewed at: http://rtlab.knu.ac.kr/robots.htm

The bit rate performance of the time hopping impulse radio UWB system with the pulse based polarity is analyzed. It is well known that the pulse polarity helps reduce the spectral spike appearing in the conventional impulse radio system. This paper provides the method for accurately modeling the multiple access interference(MAI) in the system with the pulse polarity. The characteristic function is used to consider the MAI. We also show the MAI can be simplified as Gaussian random variable when the number of pulses representing an information symbol or the pulse rate becomes large. It is obtained directly from approximating the Characteristic Function of the MAI in case of the large number of pulses. Some results have been shown to prove validity for our method. The results also show with the total processing gain fixed, increasing the pulse rates proves the system performance. But the system without the pulse polarity does not.

In this paper, we propose and analyze the Adaptive Modulation System with optimal Turbo Coded V-BLAST (Vertical-Bell-lab Layered Space-Time) technique that adopts the extrinsic information from MAP (Maximum A Posteriori) Decoder with Iterative Decoding as a priori probability in two decoding procedures of a V-BLAST scheme; the ordering and the slicing. Also, comparing with the Adaptive Modulation System using conventional Turbo Coded V-BLAST technique that is simply combined a V-BLAST scheme with a Turbo Coding scheme, we observe how much throughput performance can be improved. As a result of a simulation, it has been proved that the proposed system achieves a higher throughput performance than the conventional system in the whole SNR (Signal to Noise Ratio) range. Specifically, the result shows that the maximum throughput improvement is about 350 kbps.

In this paper, a new header compression scheme considering BCB (Basic Compression Bits) or NCB (Negotiation Compression Bits). The header compression scheme can be used for reducing the header size by eliminated repeated fields in the packet header. Here, the efficiency of the compression of the dynamic field in RTP/UDP/IP packets is very important in real-time high-speed IP networks. Our new compression method with SN and TS fields can be applicable to IPHC (Internet Protocol Header Compression), ROHC (Robust Header Compression Protocol), and other header compression schemes. The performance of the proposed scheme is discussed via simulation results.

In this paper, an enhanced time-domain cancellation method is proposed for inter-carrier interference (ICI) reduction in OFDM systems. The conventional time-domain cancellation neglects the effect of channel variation in cyclic prefix during the time-domain cancellation and does not work well in deep fades. In order to supplement the conventional method, the simple repetition (de-)coding and the modulation order increasing are employed in the time-domain cancellation. The repetition coding provides reliable symbols in the regeneration operation, and the modulation order increasing maintains or increases the spectral efficiency. Simulation results indicate that the proposed method using 16QAM significantly improves the BER performance compared to the conventional method using QPSK, while maintains the spectral efficiency. Moreover, the proposed method using 64QAM concurrently improves both the BER performance and the spectral efficiency.

The problem of scheduling transmissions of dynamic Radio Frequency Identification (RFID) systems has been recently studied. One of the common problems, reader collision avoidance has instigated researchers to propose different heuristic algorithms. In this paper, we present a prime based First Come Higher Priority (FCHP) transmission scheduling method for reader collision problems that caused by hidden terminal. FCHP is a simple mechanism for coordinating simultaneous transmissions among multiple readers. A significant improvement of this approach is that FCHP prevents reader collisions by giving contention free scheduling. The second advantage of the proposed technique is that FCHP is adaptive in both static and dynamic RFID environments. The simulation results show that the proposed technique provides superior performance in both static and dynamic instances. The FCHP is shown to be effective in terms of system throughput, system efficiency and easy to implement.

RFID systems have become vital technology for realizing ubiquitous computing environments. However, features of RFID systems present potential security and privacy problems. In an effort to resolve these problems, many kinds of security and privacy enhancement technologies have been researched. However, solutions produced to date still have flaws and are not sufficiently effective for real RFID systems such as the EPCglobal network. Therefore, in this paper, to make RFID systems more secure and efficient, improved technology based on password, is proposed. The proposed technology combines an encryption algorithm with a password-derived key, and can be applied to low-cost RFID systems for enhancing the security and privacy of these systems.

The IEEE 802.1x framework, what was known to have adjusted the IEEE 802.11b’s weakness in client authentication is a port-based control mechanism that introduces the logical port idea and performs authentication through the AP or the bridge system. Unfortunately, there are two problems in existing access authentication scheme for wireless LAN, the IEEE 802.1x. One of the problems is that it is possible for a malicious user to disguise as a right authenticator because he/she does not take into account the authentication of authenticators. The other problem is that a malicious user can force an authentication Server to waste computational resource by continuously accessing requests. In this paper, we propose a Wireless LAN secure system that offers secure encrypted communication and user authentications. The purpose of the WLAN secure system that this study suggests is to improve the weakness in security of IEEE 802.1x and to guarantee a secure encrypted communication.