A realistic computer graphics (CG) model of root growth that accounts for the effects of soil obstruction and moisture variations is proposed. While the exposed parts of plants have been modeled extensively in CG, realistic root models have received little attention, and the potential effects of root characteristics on the growth of foliage has yet to be considered in detail. The proposed model represents roots as series of bend points and link points and defines the root systems as a layered structure formed by roots connected via link points. This approach allows for two general types of root systems based on branching probabilities of lateral and adventitious roots: main root systems consisting of a thick main root and thinner lateral roots, and fibrous root systems consisting of adventitious roots of relatively uniform diameter. The model also expresses the behavior of root growth in terms of hydrotropism, gravitropism, flexion and growth inhibition by assigning gravity, moisture and consistency parameters to underground voxels. The model is shown through simulations of various growth conditions to generate individualized root systems that reflect the growth environment and characteristics of the plant.

The effect of the power/ground plane on the through-hole signal via is analyzed in a viewpoint of a band-stop filter. When the through-hole signal via passes through the power/ground plane, the return current path discontinuity of the through-hole signal via occurs due to the high impedance of the power/ground plane. Since the high impedance is produced by the power/ground plane resonance, it acts as a band-stop filter, which is connected to the signal trace in series. Therefore, the power/ground plane filters off its resonance frequency component by absorbing and reflecting from the signal on the through-hole signal via, and consequently the signal distortion, the power/ground plane noise voltage, and the consequent radiated emission occur. With S-parameter and TDR-TDT measurements, the band-stop effect of the power/ground plane on the through-hole signal via is confirmed. And then, this analysis is applied to the clock transmission through the through-hole signal via to obtain the clearer confirmation. The measurements of the distorted clock waveforms, the induced power/ground plane noise voltages, and the radiated emissions depending on the power/ground plane impedance around the through-hole signal via are shown.

The label placement problem is one of the most important problems in geographic information systems, cartography, graph drawing, and graphical interface design. In this paper, we considered the label size maximization problem for points with axes-parallel rectangular labels that correspond to character strings and have different widths based on the number of characters. We propose an algorithm for computing the optimum size for the label size maximization problem in the 2-position model and a polynomial time algorithm for the problem in the 4-position model. Our algorithm cannot obtain the maximum value in the 4-position model because the label size maximization problem in the 4-position model is NP-hard. However, our algorithm is efficient in practice, as shown by computational experiments. Further, computational results for JR trains, subways and major private railroads in Tokyo are presented.

Bi-stable displays form the foundation of a novel and attractive LCD technology. From now on, images can be maintained on the LCD after driving voltages have been withdrawn from the electrodes. In low frame-rate applications such as e-books, e-labels, smartcards etc., this offers a major improvement in power consumption and battery life. However, bi-stable displays require high driving voltages and complex waveforms. Furthermore, the nature of some applications doesn't allow the use of relatively large passive components. This rules out more traditional approaches for high-voltage generation with external coils or capacitors. This paper describes the design of completely integrated and programmable high-voltage generators capable of generating output voltages up to 50 V out of a 3 V supply voltage. Features like 8-bit output voltage programmability and stabilisation were implemented to make this type of high-voltage generator suitable for bi-stable display drivers. Design aspects and simulation results are discussed, as well as measurements on prototype generators implemented in the 0.7 µm 100 V I2T100 technology from AMI Semiconductor.

A selectively ion-implanted collector (SIC) is implemented in a 0.8 µm BiCMOS process to improve the RF characteristics of the BJT devices. The SIC BJT device has better ft and fmax than the FIC (fully ion-implanted collector) BJT device because the extrinsic base-collector capacitance is reduced by the SIC process. The ft is 7.8 GHz and fmax is 9.5 GHz for the SIC BJT device while the ft is 7.2 GHz and fmax is 4.5 GHz for the FIC BJT device when biased at Vce=3.6 V and Jc=0.07 mA/µm2. The noise parameters are the same for both BJT devices but the associated gain is higher for the SIC BJT device.

Temperature-tracking is becoming of paramount importance in modern electronic design automation tools. In this paper, we present a deterministic thermal placement algorithm for standard cell based layout which can lead to a smooth temperature distribution over the die. It is mainly based on Fiduccia-Mattheyses partition scheme and a former substrate thermal model that can convert the known temperature constraints into the corresponding power distribution constraints. Moreover, a kind of force-directed heuristic based on cells' power consumption is introduced in the above process. Experimental results demonstrate a comparatively uniform temperature distribution and show a reduction of the maximal temperature on the die.

Modern digital systems design requires us to explore a large and complex design space to find a best configuration which satisfies design requirements. Such exploration requires a sound representation of design space from which design candidates are efficiently generated, each of which then is evaluated. This paper proposes a plan-generation-evaluation framework which supports a complete process of such design space exploration. The plan phase constitutes a design space of all possible design alternatives by means of a formally defined representation scheme of attributed AND-OR graph. The generation phase generates a set of candidates by algorithmic pruning of the design space in an attributed AND-OR graph with respect to design requirements as well as architectural constraints. Finally, the evaluation phase measures performance of design candidates in a pruned graph to select a best one. A complete process of cache design is exemplified to show the effectiveness of the proposed framework.

A novel mobile assignment method based on transmit power and cell load is proposed for WCDMA base station location planning. Experimental results show that, compared with the currently widely used mobile assignment method based on link attenuation, the proposed mobile assignment method is more reasonable and unnecessary base stations are reduced in the planning results.

Stratospheric platforms have been recently proposed as a new wireless infrastructure for realizing the next generation of communication systems. To provide high quality services, an investigation of the wireless stratospheric platform channel is essential. This paper proposes a definition and describes an analysis of the wireless channel for the link between stratospheric platforms and terrestrial mobile users based on an experiment in a semi-urban environment. Narrowband channel characteristics are presented in terms of Ricean factor (K factor) and local mean received power over a wide range of elevation angles ranging from 10to 90. Finally, we evaluated average bit error probability based on the proposed channel model to examine the channel performance. For the environment in which the measurements were conducted, we find that elevation angles greater than 40yield better performance.

Displaced subdivision surface representation [13] is a new form of representing a polygonal surface model, where a detailed surface model is defined as a scaler-valued displacement map over a smooth domain surface; it puts forth a number of attractive features for editing, geometry compression, animation, scalability, and adaptive rendering of polygonal models. The construction of the smooth domain surface is a challenging task in the conversion process of a detailed polygonal surface model into this representation. In this paper, we propose a new efficient method for defining the smooth domain surface based on -subdivision scheme. The proposed algorithm not only performs better in terms of the quality of the generated surfaces but is computationally more efficient and occupies less memory as compared to the original algorithm [13] and generates surfaces with more levels of detail due to the specific nature of -subdivision when the prescribed target complexity of the generated mesh must not be exceeded. To corroborate the efficiency and the quality of the new technique, the conversion results for several public domain models have been presented.

We clarify the effective range of distance between the front and rear images of the depth-fused 3-D (DFD) visual illusion. The DFD visual illusion is perceived when two images with many edges in the front and rear frontal-parallel planes at different depths are overlapped from the viewpoint of an observer. We evaluated how the fusion of the DFD visual illusion depended on the difference in distance between the front and rear images when the distance between the two images was changed. Subjective tests clarified the cases where DFD can be applied.

A mode-matching technique in conjunction with the Floquet theorem is proposed to analyze the propagation characteristics of periodic circular surface waveguides. The circular waveguides are coated outside with a multilayered dielectric and have a ground plane with periodic corrugation of arbitrary profile. Three different ground corrugation profiles are examined to demonstrate the influences of the corrugation shape, depth, and width, dielectric thickness, and relative permittivity on bandstop characteristics.

This paper proposes a parity placement scheme, Row-Oblique Parity (ROP), for protecting against double disk failure in disk array systems. It stores all data unencoded, and uses only exclusive-or (XOR) operations to compute parity. ROP is provably optimal in computational complexity, both during construction and reconstruction. It is optimal in the capacity of redundant information stored and accessed. The simplicity of ROP allowed us to implement it within the current available RAID framework.

A novel high temperature superconducting interdigital bandpass filter is proposed by using coplanar waveguide quarter-wavelength resonators. The CPW resonators are arranged in parallel, and consequently the filter becomes very compact. The filter is a 5-pole Chebyshev BPF with a midband frequency of 5.0 GHz and an equal-ripple fractional bandwidth of 3.2%. It is fabricated using a YBCO film deposited on an MgO substrate. The measured filtering characteristics agree well with EM simulations and show a low insertion loss in spite of the small size of the filter.

In the floorplan design of System-on-Chip (SOC), Buffer Site Approach (BSA) has been used to relax the buffer congestion problem. However, for a floorplan with dominant wide bus, BSA may instead worsen the congestion. Our proposed Enhanced Buffer Site Approach (EBSA) extends existing BSA in a way that buffers of dominant wide bus can be distributed more evenly while reserving the same fast operation speed as BSA does. Experiments have been performed to integrate our model into an iterative floorplanning algorithm, and the results reveal that buffer congestion in a floorplan with dominant wide bus can be much abated.

A coplanar type lumped-element 6-pole microwave Chebyshev bandpass filter (BPF) of center frequency (f0) 2.0 GHz and fractional bandwidth (FBW) 1.0 % was designed. For the design method, theory of direct coupled resonator filters using K-inverters was employed. Coplanar type lumped-element BPFs are composed of a meander-line L and interdigital C elements. The frequency response was simulated and analyzed using an electromagnetic field simulator (Sonnet-EM). Further, the changes in f0 and FBW of the BPF were also realized by the mechanical tuning method.

Collective transverse plasma modes in Bi2Sr2CaCu2O8+x intrinsic Josephson junctions (IJJs) can be excited by the moving fluxon lattices. Progressive transformation of the standing-wave-like fluxon-lattice configuration from a triangular lattice to a rectangular lattice takes place as the dynamic fluxon-lattice modes are in resonance with the collective transverse plasma modes. In this paper, we review the progress in terahertz-frequency-range electromagnetic wave generation from the IJJs using the resonance between moving fluxon lattice and the collective transverse plasma modes.

We propose a design theory of the miniaturized high temperature superconducting (HTS) coplanar waveguide (CPW) bandpass filter (BPF), which is composed of meanderline quarter-wavelength resonator, J- and K-inverters. The J- and K-inverters are realized by using interdigital gap and meander-shape inductor. To evaluate the kinetic inductance of the K-inverter, we fabricate the YBCO resonator connected with K-inverters and redesigned the YBCO filter parameters. Finally, we designed and fabricated the YBCO CPW quarter-wavelength resonator BPF by taking account of the kinetic inductance of the K-inverter. The experimental results are in agreement with the design parameters.

The "Proactive Desk" is a new human-machine interface for the desktop operations of computers. It provides users with tactile sensation in addition to visual sensation. Two linear induction motors underneath the desk generate a two-dimensional force to move objects and control their positions on the desktop using feedback control, and users feel tactile sensation while handling those objects. In this paper, we examined the effects of adding haptic information to simple mouse operation using the Proactive Desk. In our experiment, we used a button-type visual stimulus with and without haptic information. When using haptic conditions, three types of force feedback pattern were displayed: "Edge," "Resistance to motion" and "Attractive force," and each had three force strength conditions: no, half and full. The subject was asked to push buttons twenty times as the buttons were shown one after the other on the desk as quickly as possible. Consequently, the reaction times for pushing the button for all haptic conditions, except for the half-force condition of "Attractive force," were significantly faster than no-force (without haptic information) condition. This result shows that the haptic information was advantageous for easy operation.

This study is devoted to a half-wave dipole with a conductor plane at a distance much smaller than a quarter wavelength which we designate as an ultra low profile dipole (ULPD) antenna in this paper. The concerns of ULPD antenna are the feeding method and the impedance matching, because the input impedance usually tends to be lowered by the existence of a metallic structure in its proximity. In this paper, we propose a ULPD antenna with an excellent impedance matching and a coaxial feed built within the antenna structure so that the external matching and a balun are not required. A coaxial cable is used as a feed line and extended to be a half of a half wavelength dipole. The other half is made up of a parasitic element, which is connected to the outer conductor of the coaxial radiator. To make a matching, the outer conductor of the coaxial radiator is stripped off at a suitable length, and the total length of a dipole is considered for its resonance at a desired frequency of 2 GHz. The experiment has been conducted. The results show the return loss of -27 dB and the maximum gain of 9 dBi in the normal direction to the conductor plane. The computational results are also obtained, which agree well with the experimental results.