We demonstrate a single-channel 1.28 Tbit/s-525 km transmission using OTDM of subpicosecond DQPSK signals. In order to cope with transmission impairments due to time-varying higher-order PMD, which is one of the major limiting factors in such a long-haul ultrahigh-speed transmission, we newly developed an ultrafast time-domain optical Fourier transformation technique in a round-trip configuration. By applying this technique to subpicosecond pulses, transmission impairments were greatly reduced, and BER performance below FEC limit was obtained with increased system margin.

This paper presents a systemic analysis for phase noise performances of the series quadrature oscillator (QOSC) by using the time-variant impulse sensitivity function (ISF) model. The effective ISF for each noise source in the oscillator is derived mathematically. According to these effective ISFs, the explicit closed-form expression for phase noise due to the total thermal noise in the series QOSC is derived, and the phase noise contribution from the flicker noise in the regenerative and coupling transistors is also figured out. The phase noise contributions from the thermal noise and the flicker noise are verified by SpectreRF simulations.

In this paper, the performance of the induced dimension reduction (IDR) method implemented along with the method of moments (MoM) is described. The MoM is based on a combined field integral equation for solving large-scale electromagnetic scattering problems involving conducting objects. The IDR method is one of Krylov subspace methods. This method was initially developed by Peter Sonneveld in 1979; it was subsequently generalized to the IDR(s) method. The method has recently attracted considerable attention in the field of computational physics. However, the performance of the IDR(s) has hardly been studied or practiced for electromagnetic wave problems. In this study, the performance of the IDR(s) is investigated and clarified by comparing the convergence property and memory requirement of the IDR(s) with those of other representative Krylov solvers such as biconjugate gradient (BiCG) methods and generalized minimal residual algorithm (GMRES). Numerical experiments reveal that the characteristics of the IDR(s) against the parameter s strongly depend on the geometry of the problem; in a problem with a complex geometry, s should be set to an adequately small value in order to avoid the "spurious convergence" which is a problem that the IDR(s) inherently holds. As for the convergence behavior, we observe that the IDR(s) has a better convergence ability than GPBiCG and GMRES(m) in a variety of problems with different complexities. Furthermore, we also confirm the IDR(s)'s inherent advantage in terms of the memory requirements over GMRES(m).

To reduce the inaccuracy caused by inappropriate time window, we propose two probabilistic fault localization schemes based on the idea of "extending time window." The global window extension algorithm (GWE) uses a window extension strategy for all candidate faults, while the on-demand window extension algorithm (OWE) uses the extended window only for a small set of faults when necessary. Both algorithms can increase the metric values of actual faults and thus improve the accuracy of fault localization. Simulation results show that both schemes perform better than existing algorithms. Furthermore, OWE performs better than GWE at the cost of a bit more computing time.

In this letter, an improved channel estimator for MIMO-SCBT systems is proposed. Pilot blocks are constructed using quadriphase complementary sequences (QCSs) which enable both one-sided (OSD) and two-sided (TSD) channel estimation (CE). And OSD-CE and TSD-CE are combined to provide improved performance in frequency-selective fast and slow fading channels and to maintain low-complexity implementations. Simulation results demonstrate the performance merits of the proposed scheme.

This paper presents an architecture and a circuit design of readout address compression for a high-speed 3-D range-finding image sensor using the light-section method. We utilize a kind of variable-length code which is modified to suit the 3-D range-finder. The best compression rate by the proposed compression technique is 33.3%. The worst compression and the average compression rate is 56.4% and 42.4%, respectively, when we simulated the effectivity by using the example of measured sheet scans. We also show the measurement result of the fabricated image sensor with the address compression.

Context-aware applications are a key aspect of pervasive computing. The core issue of context-aware application development is how to make the application behave suitably according to the changing context without coupling such context dependencies in the program. Several programming paradigms and languages have been proposed to facilitate the development, but they are either lack of sufficient flexibility or somewhat complex for programming and deploying. A reference programming model is proposed in this paper to make up inadequacy of those approaches. In the model, virtual tables constructed by system and maintained by space manager connect knowledge of both developer and space manager while separating dependency between context and application logic from base program. Hierarchy and architecture of the model are presented, and implementation suggestions are also discussed. Validation and evaluation show that the programming model is lightweight and easy to be implemented and deployed. Moreover, the model brings better flexibility for developing context-aware applications.

This letter presents the field uniformity characteristics of a triangular prism reverberation chamber. A reverberation chamber that generally uses a stirrer to create a uniform electric field inside is an alternative to the semi-anechoic chamber for an electromagnetic compatibility test. To overcome the size and maintenance problems of a stirrer, we propose to replace it with a Quadratic Residue Diffuser which is commonly used in acoustics. To confirm that the diffuser is a valid alternative to the stirrer, a diffuser and an equilateral triangular prism reverberation chamber are designed and fabricated for 2.3-3.0 GHz operation. To investigate the field uniformity characteristics by varying the location of the transmitting antenna, both simulation and measurement in the triangular prism reverberation chamber were also done at its two positions, respectively. A commercial program XFDTD 6.2, engaging the finite difference time domain (FDTD), is used for simulation and a cumulative probability distribution, which the IEC 61000-4-21 recommends, is used to evaluate the field uniformity. Both simulation and measurement results show that the field uniformity in the chamber satisfies the international standard requirement of 6 dB tolerance and 3dB standard deviation, which means that a diffuser can be substituted for a stirrer.

This paper presents the design of a driver amplifier (DA) for a cordless mouse application, operating at the 2.4 GHz ISM unlicensed band. The DA is a single-ended topology, and is composed of two stages: the first stage is a cascode amplifier to provide high gain and good input-output isolation, while the output stage is a simple common source amplifier that adopts a novel current reuse scheme to reduce the DC bias current by half. The DA implemented in a 0.18 µm CMOS process has a 16 dB gain at 2.4 GHz, and it can drive a 3 dBm to the antenna with an output stage drain efficiency of 31% and a power-added efficiency (PAE) of 20% while drawing 4.5 mA from a 1.8 V supply.

It is necessary to perform arithmetic in Fp12 to use an Ate pairing on a Barreto-Naehrig (BN) curve, where p is a prime given by p(z)=36z4+36z3+24z2+6z+1 for some integer z. In many implementations of Ate pairings, Fp12 has been regarded as a 6th degree extension of Fp2, and it has been constructed by Fp12=Fp2[v]/(v6-ξ) for an element ξ ∈ Fp2 such that v6-ξ is irreducible in Fp2[v]. Such a ξ depends on the value of p, and we may use a mathematical software package to find ξ. In this paper it is shown that when z ≡ 7,11 (mod 12), we can universally construct Fp12 as Fp12=Fp2[v]/(v6-u-1), where Fp2=Fp[u]/(u2+1).

Accelerator cores in low-power embedded processors have on-chip multiple memory modules to increase the data access speed and to enable parallel data access. When large functional units such as multipliers and dividers are used for addressing, a large power and chip area are consumed. Therefore, recent low-power processors use small functional units such as adders and counters to reduce the power and area. Such small functional units make it difficult to implement complex addressing patterns without duplicating data among multiple memory modules. The data duplication wastes the memory capacity and increases the data transfer time significantly. This paper proposes a method to reduce the memory duplication for window-based image processing, which is widely used in many applications. Evaluations using an accelerator core show that the proposed method reduces the data amount and data transfer time by more than 50%.

A novel one-transistor dynamic random access memory (1T DRAM) cell has been proposed for a low-voltage operation and longer data retention time. The proposed 1T DRAM cell has three features compared with a conventional 1T DRAM cell: low body doping concentration, a recessed gate structure, and a P + poly-Si gate. Simulation results show that the proposed 1T DRAM cell has < 1-ns program time and > 100-ms data retention time under the condition of sub-1-V operating voltage.

One of the most important duties of government is to maintain safety. In 2007, the Ministry of Internal Affairs and Communications of Japan tested 16 different models of a safety support system for children on school routes. One of the models was constructed and tested at a school in an area of the city of Hiroshima from September to December of 2007. A consortium was established by the city of Hiroshima; Hiroshima City University; Chugoku Electric Power Co., Inc.; and KDDI Corporation to conduct this project. For the model project, we developed a new safety support system for children on school routes by using a mobile ad hoc network constructed from mobile phones with the Bluetooth function. About 500 students and 50 volunteers used this system for four months. The support system provided good performance and accuracy in maintaining the safety of students on the way to school [7]. The basic idea of the safety support system is the grouping of children and volunteers using a mobile ad hoc network. In this paper, we present an outline of this system and evaluate the performance of grouping and the effectiveness of our approach.

In a typical SoC (System-on-Chip) design, a huge peak current often occurs near the time of an active clock edge because of aggregate switching of a large number of transistors. The number of aggregate switching transistors can be lessened if the SoC design can use a clock scheme of mixed rising and falling triggering edges rather than one of pure rising (falling) triggering edges. In this paper, we propose a clock-triggering-edge assignment technique and algorithms that can assign either a rising triggering edge or a falling triggering edge to each clock of each IP core of a given IP-based SoC/NoC (Network-on-Chip) design. The goal of the algorithms is to reduce the peak current of the design. Our proposed technique has been implemented as a software system. The system can use an LP technique to find an optimal or suboptimal solution within several seconds. The system also can use an ILP technique to find an optimal solution, but the ILP technique is not suitable to be used to solve a complex design. Experimental results show that our algorithms can reduce peak currents up to 56.3%.

The increase in the time required for data processing, mask drawing, and inspection of photomask, has led to substantial increase in mask manufacturing cost. This has become one of the major challenges in the semiconductor industry. We have developed a data flow process for mask manufacturing in which we refer to design intent information in order to reduce TAT of mask manufacturing processes. We convert design level information "Design Intent (DI)" into priority information of mask manufacturing data known as "Mask Data Rank (MDR)" so that we can identify and sort out the importance of mask patterns from the view point of the design side. As a result, we can reduce mask writing time and mask inspection time. Our objective is to build efficient data flow conversion system from DI to MDR. In this paper we introduce the idea of MDR and the software system that we built for DI extraction. Then we show the experimental results with actual chip data. Lastly we will discuss related issues and their solutions.

Aperiodic quadriphase Z-complementary sequences, which include the conventional complementary sequences as special cases, are introduced. It is shown that, the aperiodic quadriphase Z-complementary pairs are normally better than binary ones of the same length, in terms of the number of Z-complementary pairs, and the maximum zero correlation zone. New notions of elementary transformations on quadriphase sequences and elementary operations on sets of quadriphase Z-complementary sequences are presented. In particular, new methods for analyzing the relations among the formulas relative to sets of quadriphase Z-complementary sequences and for describing the sets are proposed. The existence problem of Z-complementary pairs of quadriphase sequences with zero correlation zone equal to 2, 3, and 4 is investigated. Constructions of sets of quadriphase Z-complementary sequences and their mates are given.

Let n,k,e,m be positive integers such that n≥ 3, 1 ≤ k ≤ n-1, gcd(n,k)=e, and m= is odd. In this paper, for an odd prime p, we derive a lower bound for the minimal distance of a large class of p-ary cyclic codes Cl with nonzeros α-1, α-(pk+1), α-(p3k+1), …, α-(p(2l-1)k+1), where 1 ≤ l ≤ and α is a primitive element of the finite field Fpn. Employing these codes, p-ary sequence families with a flexible tradeoff between low correlation and large size are constructed.

The structure of the nanograting channel MOSFET was optimized by simply rounding the corners of the nanogratings. The current drivabilities of the optimized nanograting channel MOSFETs were enhanced by about 20% and 50% for both n-channel and p-channel MOSFETs, respectively. The mobility changes were analyzed on the basis of channel stress as well as theoretical change of mobilities by various surface orientations. The internal compressive stress of 0.23% was measured in the channel. By suppressing the electric field increase at the corner edge of the nanograting channel to less than 10%, the fabricated rounded nanograting MOSFETs achieved lifetimes of NBTI and TDDB as long as those of conventional planar devices.

For an odd prime p, two new families of p-ary sequences of period pn-1 are constructed for odd n = 2l+1=(2m+1)e and even n = 2l = 2me, respectively. It is shown that, for a given integer ρ with 1 ≤ ρ ≤ m, the proposed sequence families both have maximum correlation magnitude , family size (pn-1)p(ρ-1)n+1, and maximum linear span .

The basic requirements of the distributed Web crawling systems are: short download time, low communication overhead and balanced load which largely depends on the systems' Web partition strategies. In this paper, we propose a DHT-based distributed Web crawling system and several DHT-based Web partition methods. First, a new system model based on a DHT method called the Content Addressable Network (CAN) is proposed. Second, based on this model, a network-distance-based Web partition is implemented to reduce the crawler-crawlee network distance in a fully distributed manner. Third, by utilizing the locality on the link space, we propose the concept of link-based Web partition to reduce the communication overhead of the system. This method not only reduces the number of inter-links to be exchanged among the crawlers but also reduces the cost of routing on the DHT overlay. In order to combine the benefits of the above two Web partition methods, we then propose 2 distributed multi-objective Web partition methods. Finally, all the methods we propose in this paper are compared with existing system models in the simulated experiments under different datasets and different system scales. In most cases, the new methods show their superiority.