Dummy Unit Research Articles

Split Manufacturing-Based Register Transfer-Level Obfuscation

Fabrication-less integrated circuit (IC) design houses outsource fabrication to third-party foundries to reduce cost of manufacturing. The outsourcing of IC fabrication, beyond our expectation, raises concerns regarding intellectual property (IP) piracy and theft by rogue elements in the third-party foundries. Obfuscation techniques have been proposed to increase resistance to reverse engineering, IP recovery, IP theft, and piracy. However, prior work on obfuscation for IP protection has primarily applied to the gate level or the layout level. As a result, it can significantly impact the performance of the original design in addition to requiring redesign of standard cells. In this article, we propose a high-level synthesis and analysis (HLSA)-based obfuscation approach for IP protection. The proposed method is based on split manufacturing. Additional dummy units and MUXes can be added to further obfuscate the design. The proposed technique aligns with the standard-cell-based design methodologies and does not significantly impact the performance of the original design. Our experimental results confirm that the proposed approach can provide high levels of IC obfuscation with moderate area cost.

Simplified Model to Predict Deflection and Natural Frequency of Steel Pole Structures

Steel pole structures are suitable alternate to transmission line towers, due to difficulty encountered in finding land for the new right of way for installation of new lattice towers. The steel poles have tapered cross section and they are generally used for communication, power transmission and lighting purposes. Determination of deflection of steel pole is important to decide its functionality requirement. The excessive deflection of pole may affect the signal attenuation and short circuiting problems in communication/transmission poles. In this paper, a simplified method is proposed to determine both primary and secondary deflection based on dummy unit load/moment method. The predicted deflection from proposed method is validated with full scale experimental investigation conducted on 8 m and 30 m high lighting mast, 132 and 400 kV transmission pole and found to be in close agreement with each other. Determination of natural frequency is an important criterion to examine its dynamic sensitivity. A simplified semi-empirical method using the static deflection from the proposed method is formulated to determine its natural frequency. The natural frequency predicted from proposed method is validated with FE analysis results. Further the predicted results are validated with experimental results available in literature.

Placement for Binary-Weighted Capacitive Array in SAR ADC Using Multiple Weighting Methods

The overall accuracy and linearity of a matching-limited successive-approximation-register analog-to-digital converter are primarily determined by its digital-to-analog converter's (DAC's) matching characteristics. As the resolution of the DAC increases, it is harder to achieve accurate capacitance ratios in the layout, which are affected by systematic and random mismatches. An ideal placement for the DAC array should try to minimize the systematic mismatches, followed by the random mismatch. This paper proposes a placement strategy, which incorporates a matrix-adjustment method for the DAC, and different placement techniques and weighting methods for the placements of active and dummy unit capacitors. The resulting placement addresses both systematic and random mismatches. We consider the following four systematic mismatches such as the first-order process gradients, the second-order lithographic errors, the proximity effects, the wiring complexity, and the asymmetrical fringing parasitics. The experimental results show that the placement strategy achieves smaller capacitance ratio mismatch and shorter computational runtime than those of existing works.

A dual-unit pressure sensor for on-chip self-compensation of zero-point temperature drift

A novel dual-unit piezoresistive pressure sensor, consisting of a sensing unit and a dummy unit, is proposed and developed for on-chip self-compensation for zero-point temperature drift. With an MIS (microholes inter-etch and sealing) process implemented only from the front side of single (1 1 1) silicon wafers, a pressure sensitive unit and another identically structured pressure insensitive dummy unit are compactly integrated on-chip to eliminate unbalance factors induced zero-point temperature-drift by mutual compensation between the two units. Besides, both units are physically suspended from silicon substrate to further suppress packaging-stress induced temperature drift. A simultaneously processes ventilation hole-channel structure is connected with the pressure reference cavity of the dummy unit to make it insensitive to detected pressure. In spite of the additional dummy unit, the sensor chip dimensions are still as small as 1.2 mm × 1.2 mm × 0.4 mm. The proposed dual-unit sensor is fabricated and tested, with the tested sensitivity being 0.104 mV kPa−1 3.3 V−1, nonlinearity of less than 0.08% · FSO and overall accuracy error of ± 0.18% · FSO. Without using any extra compensation method, the sensor features an ultra-low temperature coefficient of offset (TCO) of 0.002% °C−1 · FSO that is much better than the performance of conventional pressure sensors. The highly stable and small-sized sensors are promising for low cost production and applications.

Mismatch-Aware Common-Centroid Placement for Arbitrary-Ratio Capacitor Arrays Considering Dummy Capacitors

Switched capacitors are commonly used in analog circuits to increase the accuracy of analog signal processing and lower power consumption. To take full advantage of switched capacitors, it is very important to achieve accurate capacitance ratios in the layout of the capacitor arrays, which are affected by systematic and random mismatches. A good capacitor placement should have a common-centroid structure with the highest possible degree of dispersion to mitigate mismatches. Several dummy units should be inserted to make the placement shape more square and compact. This paper proposes a simulated-annealing-based approach for mismatch-aware common-centroid placement under the above constraints. A pair-sequence representation is used to record a placement, and a couple of associated operations are developed to find better solutions. The experimental results show that the proposed placements achieve smaller oxide-gradient-induced mismatch and larger overall correlation coefficients (i.e., higher degree of dispersion) than those of previous works.

Productivity and photosynthetic efficiency of outdoor cultures of Tetraselmis suecica in annular columns

In this study, 120-l annular columns were used to cultivate Tetraselmis suecica outdoors. The mass transfer at different aeration rates and the influence of the harvest rate on productivity and biochemical composition were investigated. The potential of the system was evaluated by estimating productivity at full-scale. Two different arrangements to simulate a full-scale plant and determine the “overall areal productivity” (OAP) were experimented with. In August 2003, one experimental column (full-scale column) was placed between seven dummy columns. All the reactors were positioned at a distance of 0.8 m wall to wall and centred at the vertices of equilateral triangles. A second experimental column (isolated column) was placed in a separate area under full sunlight. In August 2004, the columns were placed side by side in an east–west oriented row at a distance of 0.24 m wall to wall. In the first experiment, the mean volumetric productivity of the full-scale column was not significantly lower than that achieved by the isolated column (0.46 against 0.49 g l − 1 day − 1 ) in spite of the shading by the dummy units. The average OAP and efficiency of conversion of visible solar radiation (PE) were 36.3 g m − 2 day − 1 and 9.4%, respectively. In the second experiment, the full-scale column attained a mean volumetric productivity of 0.42 g l − 1 day − 1 . The OAP and the PE were 38.2 g m − 2 day − 1 and 9.3%, respectively.

On structured fault tree construction by modularizing control loops

Abstract The objectives of this article are: (1) to develop the fault trees for control loops in a way that they all appear in a proper form and as modules in the fault tree for the whole system; and also (2) to modularize each control loop in a system properly to establish its unit model. These two methods are essentially equivalent. Either of them can be applied to facilitate constructing fault trees for the whole system. To accomplish such equivalent or parallel objectives, we will first take the feedback and feedforward control loops in the heat exchanger system as examples and then: (1) construct the fault trees of deviations in controlled variable for the two control loops in the way that all of their non-basic terminal events should be deviations in variables on those streams that connect to the loop from their outside in the system; and (2) establish the unit model for each of such two loops. One of the purposes of (2), which will not be addressed here, is to regard each control loop as a dummy unit and hence reduce the system to facilitate system input and fault tree construction eventually for complete automation purpose.

Operational experience with the tubular-space structure designed by the Moscow Architectural Institute for the machine gallery at the Sayano-Shushenskoe hydroelectric power plant

1. In designing heavy-duty high-head hydraulic facilities, where significant hydrodynamic effects on elements of the hydraulic facility should be expected during operation of dummy spillways and units, it is necessary to perform their dynamic calculation. 2. The MARCHI-designed superstructure of the machine gallery at the Sayano-Shushenskoe hydroelectric power plant is subject to rather vigorous vibrations due, in particular, to the operation of the dam's spillways. Nontraditional structural solutions with respect to the installation of dynamic dampers, which may be adopted after appropriate computational and field investigations, are required for this structure to lower the swings of the oscillations. 3. Development of maximum oscillations in strictly defined areas occurs not as a result of different stiffnesses of the components of the superstructure of the machine gallery at the Sayano-Shushenskoe hydroelectric plant or the stiffness of the reinforced-concrete unit blocks, but most likely due to the mutual effect of various elements of the hydraulic facility as sources of wave oscillations that develop due to the effect of hydrodynamic forces during idle discharges on the toe basin.

Structured fault tree synthesis based on system decomposition

The purpose of this article is to explain how to decompose a system so that its fault trees can be synthesized more efficiently and in a structured and recursive manner. Under such a decomposition, modules such as control/trip loops will be regarded as dummy units at first so that the system size can be reduced significantly and dramatically. The fault tree of a top event can thus be constructed as follows: the one for the reduced system is synthesized first and then each of its terminal events, when these are events of a dummy unit, will be further developed. In order to carry out such a synthesis automatically, each dummy unit must be tried first, in order to be standardized, so that its unit-model can be established, and then saved in a database in advance. A suitable system input format must also be designed so that the fault tree can be synthesized automatically simply by keying-in the top event and the system.

Comparison of Wind-Tunnel and Flight-Test Heat-Transfer Measurements on a Pylon-Mounted Store

Flight and wind-tunnel tests were conducted on a pylon-mounted store. The purpose of these tests was to substantiate the extrapolation procedures used to determine heating rates on a full-scale Bomb Dummy Unit from those measured on a 1/15-scale model o Some substantiating evidence was obtained; however, scatter in the flight-test data prohibited any definite conclusion. The flight-test phase did produce excellent flow visualization pictures by applying phase-change paint to the store.

Plastic Dummy Heat Exchangers

DURING the past three years, the aircraft industry has increased considerably its use of plastic models, jigs and fixtures for checking, assembly and drilling operations, and, to take but one example, Vickers‐Arinstrongs (Aircraft) Ltd. have simplified and have specded‐up the production and fitting of heat exchanger units in the B.A.C. One‐Eleven short‐haul airliners by using plastic dummy units.