Round Operation Research Articles

Influence of the edge rounding process on the behaviour of blanked parts: numerical predictions with experimental correlation

Blanking of sheet metal is an important forming process in the automotive industry for the manufacture of mechanical components. The final component shape, obtained at the end of bending or deep-drawing processes, often has sharp edges due to the blanking operation. Concerning passenger safety components, like seat belt anchors, rounding of the edges by punching is necessary to avoid cutting the belt material. In addition to removing the sharp edges, the punching results in work hardening of the material in the rounded zones which results in an increase in the local resistance of the material. In this study, a high-strength low-alloy steel (HSLA S500MC) has been tested with the aim of quantifying the blanking and edge rounding operations. The mechanical behaviour of test specimens is investigated by means of tensile tests and the material is characterised in terms of Vickers micro-hardness. Numerical simulations of the edge rounding process are developed using previously identified material behaviour laws. The residual stress fields are characterised and compared to experimental results. This is done so that numerical simulation can be done in the future to prediction the in-service behaviour of the component. Specimens with rounded edges are compared to specimens that were not submitted to the rounding operation. It is shown that Edge Rounding by Punching improves the component resistance, therefore justifying the use of this process in the manufacture of automotive safety components.

Energy conservative air conditioning system using silver nano-based PCM thermal storage for modern buildings

This work aims at improving the thermal performance and energy efficiency of chilled water based variable air volume air conditioning system integrated with the silver nanoparticles embedded latent thermal energy storage system. The latent thermal energy storage air conditioning system incorporated with the demand controlled ventilation and the economizer cycle ventilation schemes were experimentally investigated for the year-round building air conditioning application. Phase change material embedded with silver nanoparticles enabled it to exhibit improved heat transfer mechanisms in charging and discharging cycles. Experimental results suggest that the proposed air conditioning system achieved an on-peak and per day average energy savings potential of 36–58% and 24–51%, respectively, for year round operation while compared to the conventional air conditioning system. Similarly, while compared with a basically similar variable air volume air conditioning system, the proposed air conditioning system yielded 7.5–18.6% and 7.9–17.8% of on-peak and per day average energy conservative potential, respectively. Furthermore, test results infer that the combined effects produced by the silver nanoparticles embedded latent thermal energy storage system with the ventilation techniques augmented the overall thermal performance of the system. In total, the combined air conditioning system would be beneficial in terms of accomplishing good thermal comfort, acceptable indoor air quality and energy redistribution needs in buildings without sacrificing energy efficiency.

Collision Analysis and Improvement of a Parallel Hash Function based on Chaotic Maps with Changeable Parameters

Recently, a parallel hash function based on chaotic maps with changeable parameters was proposed by Li et al (2011, pp.1305-1312). In this paper, the security of it is analyzed and the weakness of the architecture is pointed out. It is found that the main limitations are the error using of floor, round and exclusive OR operations in the algorithm. In order to counterstrike these, some improvements are done to strength its security. Theoretical analysis and experimental results illustrate that the improved Hash function is more secure and practical than the original one.

DIFFERENTIAL PROPERTIES OF SYMMETRIC BLOCK CIPHERS WITH ROUND KEY MODULAR OPERATIONS OTHER THAN XOR

Symmetric block ciphers differential properties with variousround key operations are considered. It is shown that knownciphers with round operations other than XOR after small initialencryption rounds acquire random substitution properties ofcorrespondent degree, but they achieve stationary maximal valuetwo times smaller than maximal value acquired for round operationas bitwise XOR. It is concluded that application of round operationsother than XOR does not lead to significant growth of provablecipher strength. It is mentioned that all iterative ciphersindependently of round key operation type give the same maximalvalues of full differentials according to difference computationoperation as bitwise XOR.

TOLERANCE DESIGN OF ANALOG CIRCUITS USING A BRANCH-AND-BOUND BASED APPROACH

The design of circuits which are robust against variations in operating and process conditions is crucial in today's IC industry. In the analog design flow this problem can be tackled during the sizing of a new circuit. However, hardly any methods are available which support the designer to compute such a robust design if discrete parameters should be considered in this design step. Discrete parameters arise predominantly if a layout-friendly sizing should be computed in the sense that, e.g., a manufacturing grid for the transistor lengths and widths is considered or that transistor multipliers are used to allow the layout of a transistor as multifinger or common centroid structure without applying rounding operations to the carefully computed sizing. This paper presents a new Branch-and-Bound based approach which allows the automatic computation of a robust design using classical and realistic worst case analysis. The results of the sizing of three circuits show that the new approach is highly efficient. The robustness of the results computed by the new approach is validated by Monte Carlo analyses.

Transmission media appropriate laser-microwave solar power satellite system

As a solution to the most critical problems with Solar power Satellite (SPS) development, a system is proposed which uses laser power transmission in space to a receiver high in the atmosphere that relays the power to Earth by either cable or microwave power transmission. It has been shown in the past that such hybrid systems have the advantages of a reduction in the mass of equipment required in geostationary orbit and avoidance of radio frequency interference with other satellites and terrestrial communications systems. The advantage over a purely laser power beam SPS is that atmospheric absorption is avoided and outages due to clouds and precipitation will not occur, allowing for deployment in the equatorial zone and guaranteeing year round operation. This proposal is supported by brief literature surveys and theoretical calculations to estimate crucial parameters in this paper.In relation to this concept, we build on a recently proposed method to collect solar energy by a tethered balloon at high altitude because it enables a low-cost start for bringing the first Watt of power to Earth giving some quick return on investment, which is desperately missing in the traditional SPS concept.To tackle the significant problem of GW-class SPSs of high launch cost per kg mass brought to space, this paper introduces a concept which aims to achieve a superior power over mass ratio compared to traditional satellite designs by the use of thin-film solar cells combined with optical fibres for power delivery. To minimise the aperture sizes and cost of the transmitting and receiving components of the satellite and high altitude receiver, closed-loop laser beam pointing and target tracking is crucial for pointing a laser beam onto a target area that is of similar size to the beam's diameter. A recently developed technique based on optical phase conjugation is introduced and its applicability for maintaining power transmission between the satellite and high altitude receiver is assessed.It was found that the design of the high altitude receiver and the means of transporting the received power through the lower 21km of the atmosphere are inextricably linked. It was concluded that an initial small scale low-cost demonstration flight of the receiver that delivers power using existing technology could be undertaken in the near future.

Enhanced Adaptability of Tilling Robot (Initial Report)

The tilling robot mainly comprises: a robot vehicle called ROBOTRA, which is remodeled to control parts of commercially available tractors automatically, a navigation system called XNAV, which detects and outputs robot positioning information using an auto-tracking type surveying device, and a controller with read operation software to execute path planning and control the robot vehicle. The robot has ability almost equivalent to that of customary manned-driven tractors and can perform unmanned rotary tilling on a rectangular field. To improve its adaptability during unmanned operation, we remodeled it so that it could perform path operations differing from customary rotary tilling and performed field tests. We proposed two different path operation methods: “diagonal operation”; performing returning straight operations diagonally against the longer side of the field; and “round operation”; performing straight operations parallel to the four sides in the entire field area, and developed a software package for the same. Following field tests using the software, we confirmed that favorable unmanned operation could be achieved through both methods.

Clinical investigation of surgical iris reposition through segmental small incision for iridodiastasis

Objective To discuss the effect of surgical iris reposition through segmental small incision on iridodiastasis. Methods We made iris plasty surgery by repositing the root of iris through segmental small incision on 63 patients (63 eyes) of traumatic iridodiastasis. Results The iris was reposited successfully in all the patients. No complication was observed. The pupil showed a round or oval shape ater operation. The symptom of diplopia disappeared. Conclusion Segmental small incision method is an microtraumatic, safe, simple and effective surgery. Key words: iridodiastasis,traumatic; iris plasty; reposition

A quantization-based semi-fragile watermarking scheme for image content authentication

This paper presents a novel semi-fragile watermarking scheme for image content authentication with tampering localization. The proposed scheme uses a non-traditional quantization method to modify one chosen approximation coefficient of each non-overlapping block to ensure its robustness against incidental attacks and fragileness against malicious attacks. The image content authentication starts with extracting watermark using the parity of quantization results from the probe image, where the round operation is used to ensure the semi-fragile property. It then constructs a binary error map and computes two authentication measures with M 1 measuring the overall similarity between extracted and embedded watermarks and M 2 measuring the overall clustering level of tampered error pixels. These two measures are further integrated to confirm the image content and localize the possible tampered areas. Our experimental results show that our scheme outperforms four peer schemes and is capable of identifying intentional tampering and incidental modification, and localizing tampered regions.

On the Implementation of Spread Spectrum Fingerprinting in Asymmetric Cryptographic Protocol

Digital fingerprinting of multimedia contents involves the generation of a fingerprint, the embedding operation, and the realization of traceability from redistributed contents. Considering a buyer's right, the asymmetric property in the transaction between a buyer and a seller must be achieved using a cryptographic protocol. In the conventional schemes, the implementation of a watermarking algorithm into the cryptographic protocol is not deeply discussed. In this paper, we propose the method for implementing the spread spectrum watermarking technique in the fingerprinting protocol based on the homomorphic encryption scheme. We first develop a rounding operation which converts real values into integer and its compensation, and then explore the tradeoff between the robustness and communication overhead. Experimental results show that our system can simulate Cox's spread spectrum watermarking method into asymmetric fingerprinting protocol.

A Selective Encryption Algorithm Based on AES for Medical Information

ObjectivesThe transmission of medical information is currently a daily routine. Medical information needs efficient, robust and secure encryption modes, but cryptography is primarily a computationally intensive process. Towards this direction, we design a selective encryption scheme for critical data transmission.MethodsWe expand the advandced encrytion stanard (AES)-Rijndael with five criteria: the first is the compression of plain data, the second is the variable size of the block, the third is the selectable round, the fourth is the optimization of software implementation and the fifth is the selective function of the whole routine. We have tested our selective encryption scheme by C++ and it was compiled with Code::Blocks using a MinGW GCC compiler.ResultsThe experimental results showed that our selective encryption scheme achieves a faster execution speed of encryption/decryption. In future work, we intend to use resource optimization to enhance the round operations, such as SubByte/InvSubByte, by exploiting similarities between encryption and decryption.ConclusionsAs encryption schemes become more widely used, the concept of hardware and software co-design is also a growing new area of interest.

Enhancement of cooling capacity in a hybrid closed circuit cooling tower

Performance characteristics of the Hybrid Closed Circuit Cooling Tower (HCCCT) have been tested experimentally. Bare-type copper tubes and fin tubes were used in staggered arrangement at the heat exchanger of the HCCCT and the cooling capacity and pressure drop have been studied from various perspectives. The relevant temperatures and velocities were selected based on the typical East Asian meteorological constraints for the year round operation of the HCCCT. Performance characteristics were compared and found that for the fin tubes, cooling capacities were about 22% and 260% higher than those of the bare tubes in wet and dry modes, respectively. The pressure drop for the fin tubes was nearly two times higher than that of the bare tubes in both modes. The experimental results show considerable enhancement of cooling capacity.

Relative blending

Solid models may be blended through filleting or rounding operations that typically replace the vicinity of concave or convex edges by blends that smoothly connect to the rest of the solid’s boundary. Circular blends, which are popular in manufacturing, are each the subset of a canal surface that bounds the region swept by a ball of constant or varying radius as it rolls on the solid while maintaining two tangential contacts. We propose to use a second solid to control the radius variation. This new formulation supports global blending (simultaneous rounding and filleting) operations and yields a simple set-theoretic formulation of the relative blending R B ( A ) of a solid A given a control solid B . We propose user-interface options, describe practical implementations, and show results in 2 and 3 dimensions.

Constructing a one-way hash function based on the unified chaotic system

A new one-way hash function based on the unified chaotic system is constructed. With different values of a key parameter, the unified chaotic system represents different chaotic systems, based on which the one-way hash function algorithm is constructed with three round operations and an initial vector on an input message. In each round operation, the parameters are processed by three different chaotic systems generated from the unified chaotic system. Feed-forwards are used at the end of each round operation and at the end of each element of the message processing. Meanwhile, in each round operation, parameter-exchanging operations are implemented. Then, the hash value of length 160 bits is obtained from the last six parameters. Simulation and analysis both demonstrate that the algorithm has great flexibility, satisfactory hash performance, weak collision property, and high security.

Direction-Variable Beam by Decentered Annular Array Sound Source with Rounded Width of Elements

In this paper, we describe an examination of a direction-variable beam generated by a sound source that causes the decentering operation of the equiamplitude-driven annular array. In the presented method, we apply a rounding operation for the width of each annular array element. From results of the calculations carried out for examining the effect on the shape of the radiated sound beams, it is shown that the beam profiles exhibit no marked turbulence in comparison with the profile in which the rounding operation is not applied, as long as the number of array elements and the central radius of the outermost element satisfy the desired value. It is expected that these results will enable the simplification of the process for forming the array element, in the actual production of sound sources.

The Global Software Industry Evaluating the Software Markets of the BRIC Nations

The world software industry and associated markets are estimated to be worth 1.1 trillion US Dollars, ninety percent of the world's exports in software is from the United States and Europe evidence would also suggest that outside the United States and Europe, the new and emerging countries within the software industry are Brazil, Russia, India and China (known as the BRIC Nations). The Software industry greatly affects the economic systems of these countries. Although figures vary these emerging markets account currently for around 6 per cent of global export markets. While “lower cost labour” is the most commonly cited reason for offshoring, intense global competition in an environment of slower growth and low inflation demands constant vigilance over costs. Due to low costs and high quality, using offshore resources in selected countries seems to make good economic sense. Beyond the cost incentive, global sourcing provides several other practical benefits including: the ability of multinational organisations to efficiently stage all year round operations; the opportunity to customize products and services to meet local needs; and the means of geographically deploying workers and facilities to succeed in globally dispersed, highly competitive markets. This paper examines some of the issues within these emerging countries within the wider global software industry.

Four-band decomposition module with minimum rounding operations

A four-band decomposition module for 2D digital signals is proposed. The total amount of the error due to the rounding operation is reduced under the constraint that the module has compatibility with the conventional wavelet transform in JPEG 2000. The number of rounding operations and the standard deviation of the error are reduced by 33.3 and 22.9%, respectively, per one module.

Roundness Modeling Using Fractal Interpolation

There are many modelling methods using theoretical and experimental data. Recently, fractal interpolation methods have been widely used to estimate and analyse various data. Due to the chaotic nature of dynamic roundness profile data in roundness, some desirable method must be used for the analysis of data which is natural to sequential data. Fractal analysis used in this paper is within the scope of the fractal interpolation and fractal dimension. Also, two methods for computing the fractal dimension have been introduced, which can calculate the fractal dimension of typical dynamic roundness profile data according to the number of data points in which the fixed data are generally lower than 120 data points. This fractal analysis shows a possible prediction and analysis of roundness profile that has some different roundness profile in round shape operation such as cylindrical grinding, turning, drilling and boring.

Isolating Blocks for Periodic Orbits

In this article, we prove that the Lyapunov semi-graphs associated with periodic orbits are realizable by constructing isolating blocks N n for periodic orbits of Morse---Smale flows. We analyze the effects on the Betti numbers of a manifold after performing a round handle operation and considering a variety of situations. Since we are concerned in showing the existence of certain blocks, we keep the complexity of the manifolds in consideration under control by considering mainly manifolds with free homology groups, in particular, we consider connected sums of tori manifolds.

Fast-matched filters in time domain for global positioning system receivers

A fast-matched filter algorithm in time domain is presented to correlate signals for optimal detection of signals in noise, to extract ranging measurements, for synchronisation, and so on. The matched filters are discussed in the context of global positioning system receivers, but the algorithms presented here can be directly used for other direct sequence spread spectrum receivers as no constraining assumptions are made in the derivations. The method proposed here outperforms the conventional time-domain method several times in arithmetic complexity. It is also competitive with transform-domain techniques based on fast Fourier transform (FFT). Unlike FFT-based methods, however, this approach is accurate and does not use rounding or scaling operations.