A multiple-places reservation discipline is studied in a discrete-time priority queueing system. We obtain the joint distribution of system state, from which the delays of high and low priority packets are derived. Comparison is made with the cases of FIFO, single-place reservation discipline and HOL priority.

Gastric cancer is a great part of the cancer occurrence and the mortality from cancer in Korea, and the early detection of gastric cancer is very important in the treatment and convalescence. This paper, for the early detection of gastric cancer, proposes the analysis system of an endoscopic image of the stomach, which detects abnormal regions by using the change of color in the image and by providing the surface tissue information to the detector. While advanced inflammation or cancer may be easily detected, early inflammation or cancer is difficult to detect and requires more attention to be detected. This paper, at first, converts an endoscopic image to an image of the IHb (Index of Hemoglobin) model and removes noises incurred by illumination and, automatically detects the regions suspected as cancer and provides the related information to the detector, or provides the surface tissue information for the regions appointed by the detector. This paper does not intend to provide the final diagnosis of abnormal regions detected as gastric cancer, but it intends to provide a supplementary mean to reduce the load and mistaken diagnosis of the detector, by automatically detecting the abnormal regions not easily detected by the human eye and this provides additional information for diagnosis. The experiments using practical endoscopic images for performance evaluation showed that the proposed system is effective in the analysis of endoscopic images of the stomach.

In this paper, the problem of Redundant Duplicated RREQ Network-wide Flooding (RDRNF), induced by multiple sensor nodes during route discovery in event-driven wireless sensor networks, is described. In order to reduce the number of signaling messages during the route discovery phase, a novel extension, named the Localized Route Discovery Extension (LRDE), to the on-demand ad hoc routing protocol, is proposed. The LRDE reduces energy consumption during route discovery. The heuristically and temporarily selected Path Set-up Coordinator (PSC) plays the role of a route request broker that alleviates redundant route request flooding. The LRDE also sets a route path be aggregation-compatible. The PSC can effectively perform data aggregation through the routing path constructed by the LRDE. The simulation results reveal that significant energy is conserved by reducing signaling overhead and performing data aggregation when LRDE is applied to on-demand routing protocols.

Frequency-modulated clock signals are widely used in personal computers to reduce the amplitude of the clock harmonic noise, as measured using an electromagnetic interference (EMI) test receiver. However, the power of the clock harmonics is not decreased with this technique called spread spectrum clocking (SSC). Hence, the impact of the harmonics of a frequency-modulated clock on the bit error rate (BER) and packet error rate (PER) of a Bluetooth system is theoretically analyzed. In addition, theoretical analysis covers the effectiveness of a frequency hopping spread spectrum (FH-SS) scheme and forward error correction (FEC) in mitigating the degradation in the BER and PER caused by clock harmonic interference. The results indicate that the BER and PER strongly depend on the modulating frequency and maximum frequency deviation of the clock harmonic. They also indicate that radiated clock harmonics may considerably degrade the BER and PER when a Bluetooth receiver is very close to a personal computer. Frequency modulating the clock harmonics slightly reduces the BER while it negligibly reduces the PER.

Scheduling algorithms are playing a key role in overall system performance of broadband wireless systems (BWS). Maximal SNR (MaxSNR) and Round Robin (RR) are two conventional scheduling strategies which emphasize efficiency and fairness respectively. Proportional Fair (PF) algorithm provides tradeoff between efficiency and fairness. In this paper, we apply PF to IEEE 802.16a OFDM based BWS and name it OPF. We also propose a new algorithm for multimedia services: Normalized Multimedia Adaptive OPF (NMAOPF). Adaptive modulation and coding scheme is applied in time varying and frequency selective fading wireless channel. System performances are compared in efficiency and fairness with and without user mobility. Efficiency is in terms of throughput, mean packet delay and packet drop ratio; fairness is in terms of user satisfaction rate and average user rate. Joint PHY and MAC layer simulation results show that: within the traffic range of 55 to 70 Mbps, compared with RR and MaxSNR, the performance of OPF is in between. Our proposed NMAOPF outperforms all others without user mobility, while under mobility, it is not as good as MaxSNR but better than OPF and RR.

We investigated luminescent properties in combination of red emissive europium complex of tris(dibenzoylmethane)-mono(4,7-dimethylphenanthroline)europium(III) [Eu(dbm)3phen] and blue phosphorescent molecule of bis[(4,6-difluorophenyl)-pyridinato-N,C2'] (picolinate) iridium (III) (FIrpic) doped in poly(N-vinyl-carbazole) (PVK). A sharp red emission from Eu(dbm)3phen was observed in photoluminescence (PL) measurement, whereas, in the case of electroluminescence (EL), emission from FIrpic and Eu compound were observed. The difference of the PL and EL spectra indicates that different energy transfer processes between Eu(dbm)3phen and FIrpic are suggested.

There is a certain level of requirements for system performance that intrusion detection systems on the Internet need. One of them is to lower the rate of "False Positive" and "False Negative." Another one is to have a convenient user interface so that users can manage system security easily with the detection systems. However, scan detection systems on public domain show a high rate of false detection and have difficulty in detecting various scanning techniques. In addition, since current scan detection systems are based on the command interface, the systems have been poor at user interface and therefore it is difficult to apply them to system security management. Hence, we first propose a set of new filter rules, which detect various scan attacks based on port scanning techniques. Secondly, a set of ABP-Rules derived from attacker's behavioral patterns is proposed in order to minimize the False Positive rate. With these methods, we implement a new real-time scan detection system, overcoming the limitations of current real-time scan detection systems. Also the implemented system contains a GUI interface for user's convenience of managing the network security, which was developed with Tcl/Tk.

A high-speed drive technique is introduced in which addressing is done by eliminating, instead of accumulating, the wall charges. In the proposed scheme, wall charges are accumulated in all the cells in advance, and then the address discharges take place in selected cells to eliminate the wall charges. Sustain discharges are generated in these cells. In order to realize the proposed address scheme, re-designing of a setup waveforms was necessary. The data pulse of 1.33 µs wide and 84 V was realized in a Ne+10%Xe PDP. A contrast of 3,600:1 was obtained by providing one setup period in a TV field.

LSI testing is critical to guarantee chips are fault-free before they are integrated in a system, so as to increase the reliability of the system. Although full-scan is a widely adopted design-for-testability technique for LSI design and testing, there is a strong need to reduce the test data Volume, scan-in Power dissipation, and test application Time (VPT) of full-scan testing. Based on the analysis of the characteristics of the variable-to-fixed run-length coding technique and the random access scan architecture, this paper presents a novel design scheme to tackle all VPT issues simultaneously. Experimental results on ISCAS'89 benchmarks have shown on average 51.2%, 99.5%, 99.3%, and 85.5% reduction effects in test data volume, average scan-in power dissipation, peak scan-in power dissipation, and test application time, respectively.

A new compact line equalizer is proposed for backplane serial link applications. The equalizer has two control blocks. The feed-forward swing control block determines the optimal low frequency level and the feedback control block detects signal shapes and decides the high-frequency boosting level of the equalizer. Successful equalization is demonstrated over a 1.5 m long PCB trace at 3.125-Gb/s by the circuit realized with 0.18 µm CMOS process. The circuit occupies only 0.16 mm2 and consumes 20 mW with 1.8 V supply.

A linear CMOS transconductor is presented. PMOS transistors are employed in the resistor-replacement and voltage-level shifting to avoid the body effect. To annihilate the non-linear voltage terms, the substrate-bias effect of MOS transistors is treated more accurately in our design. Consequently, the non-linearity of the large-signal transconductance is reduced. The fabricated circuit occupies an area of 245 µm176 µm ( ≈approx 0.043 mm2) and dissipates 0.87 mW from a 3.3 V supply. For an input of 1 Vp-p, the measured output total harmonic distortion is less than 1.2%. The transconductance varies by less than 0.5% in the input range.

An optically scanning electromagnetic field probe system consisting of an electro-optic or magneto-optic crystal and a galvano scanner is proposed for high-speed electromagnetic field distribution measurements. We used this technique to measure electromagnetic field distributions near printed circuit boards or ICs to address electromagnetic compatibility problems or in designing electronic devices. With our scanning system, we can measure the electric field intensities of about 40,000 points with an area of 4040 mm in about 3 minutes (4 ms per point) up to 2.7 GHz. We measured the electric near-field distribution above a five-split transmission line using a cadmium telluride (CdTe) electro-optic crystal. The measurement results showed that the spatial resolution of the system was less than 400 µm in the case of a common current with a crystal thickness of 1 mm. The electric near-field distribution above a microstrip line filter was measured using LiNbO3 electro-optic crystal. Changes in the distribution according to the frequency were observed. The experimental results obtained using this system were compared with simulation results obtained using a finite-difference time-domain method. The overall results indicated that the measurement system is capable of accurately measuring electric near-fields. We also discuss the invasiveness of the measurement system, due to the electro-optic crystals, in terms of both the experimental and simulated results.

In this paper the attention is focused on the numerical study of hyperchaotic 2D-scroll attractors via the Adomian decomposition method. The approach, which provides series solutions of the system equations, is first applied to weakly-coupled Chua's circuits with Hermite interpolating polynomials. Then the method is successfully utilized for achieving hyperchaos synchronization of two coupled Chua's circuits. The reported examples show that the approach presents two main features, i.e., the system nonlinearity is preserved and the chaotic solution is provided in a closed form.

Video transcoding technique is an efficient mechanism to deliver visual contents to a variety of users who have different network conditions or terminal devices with different display capabilities. In this paper, we propose two types of transcoding methods for adapting the bitrate of streaming video to the bandwidth of the transmission channel; spatial resolution reduction (SRR) transcoding and temporal resolution reduction (TRR) transcoding. The two transcoding methods are alternatively operated according to the requirements of users. Experimental results show that the proposed transcoding methods can preserve image quality while transcoding to the low bitrate.

Receiver enhancement at mobile terminals such as using receiver diversity is a way of achieving greater downlink capacity. The enhancement, however, is achieved not instantaneously by a network operator but gradually by the individual users that choose and purchase their own mobile terminals. We investigate in this letter the effect of gradually introducing enhanced receivers at mobiles in different locations. With greedy scheduling, capacity, fairness and coverage are quantified and numerically compared according to locations of enhanced mobiles. The results show that the enhancement made at mobiles nearer to the base provides the greater capacity but this capacity-driving introduction of the enhancement makes the fairness and the coverage poorer.

We have developed a stereoscopic large LED display with parallax barrier for use by the general public and stereoscopic cameras to show real world images in 3D. This paper aims to analyze stereoscopic camera separation and convergence angle to make the most use of a field of interest and the reproducible space provided by the large stereoscopic LED display. We describe the principle of a stereoscopic LED display with a parallax barrier and its reproducible space that is determined by the allowable range of disparity to fuse stereoscopic images. By using a model of stereoscopic imaging and display process, we introduce the formulas of the reproduced positions on our developed stereoscopic LED display. Furthermore, we analyze relationships between the stereoscopic camera separation, the convergence angle, the area of a field of interest, and the depth range of the reproduced space. The results show there are four categories in camera configurations: there are three kinds of camera configurations that have different characteristics and one configuration that is not recommended. Category A configuration reproduces a wide area of the field of interest in a long range of depth. Category B functions as a reduction of the field of interest. Category C functions as a magnification of the field of interest. In Category D, a narrow area of the field is reproduced in a short range of depth. In particular, for use by stereoscopic LED display with a rather low resolution, Category A and Category C are recommended because they fully use the reproducible positions.

In this paper, we shall describe about a refined theory based on the concept of set-valued operators, suitable for available operation of extremely complicated large-scale network systems. The deduction of theory is accomplished in a weak topology introduced into the Banach space. Fundamental conditions for availability of system behaviors of such network systems are clarified, as a result, in a form of fixed point theorem for system of set-valued operators.

We propose a new fixed-rate error correction system with a feedback channel. In our system, the receiver transmits a list of positions of unreliable information bits based on the log a-posteriori probability ratios by outputs of a soft-output decoder to the transmitter. This method is just like that of the reliability-based hybrid ARQ scheme. To dynamically select an appropriate interleaving function with feedback information is a key feature of our system. By computer simulations, we show that the performance of a system with a feedback channel is improved by dynamically selecting an appropriate interleaving function.

This letter presents a new gossip-based ad hoc service discovery protocol that uses a novel decentralized, peer-to-peer mechanism to provide mobile devices with the ability to advertise and discover services in an efficient way. Our performance study shows that the proposed protocol appropriately addresses the need of proximal service discovery over a dynamic wireless medium.

This paper proposes a wideband speech coder in which a G.711 bitstream is embedded. This coder has an advantage over conventional coders in that it has a high interoperability with existing terminals so costly transcoding involving decoding and re-encoding can be avoided. We also propose a partial mixing method that effectively reduces the mixing complexity in multiple-point remote conferences. To reduce the complexity, we take advantage of the scalable structure of the bitstream and mix only the lower band of the signal. For the higher band, the main speaker location is selected among remote locations and is redistributed with the mixed lower-band signal. By subjective evaluations, we show that the speech quality can be maintained even when the speech signals are partially mixed.