Three-step Design Research Articles

Design optimisation procedure for digital mismatch compensation in latch comparators

Digital calibration schemes generally allow for high-speed operation and reduced power consumption at the price of lower accuracy compared with their analogue counterparts. However, in dynamic comparators, when exceeding 4 or 5 bits, any resolution increase will be progressively traded against the circuit parameters. This study presents a three-step design procedure to optimise the comparator performance for a given N . First, a new configuration of the latch comparator has allowed optimising the comparison speed in terms of N . Second, the calibration scheme has been reduced to a simple digital sequencer to perform a progressive capacitive offset trimming. Third, the sequencer automatic increment has been programmed to stop at optimal operation to achieve the best calibration accuracy. The proposed method has then been applied to design a latch comparator with 7 bit calibration control in a commercially available 0.18 μm complementary metal-oxide-semiconductor technology. Post-layout statistical simulations have shown that the circuit can achieve up to 5.9 bit calibration resolution without altering the comparator performances.

Design Strategy for the Molecular Functionalization of Semiconductor Photoelectrodes: A Case Study of p-Si(111) Photocathodes for H2 Generation.

Functionalization of semiconductor photoelectrodes is actively pursued as an approach to improve the efficiency of photoelectrochemical reactions by modulating the semiconductor's barrier height, but the selection of molecules for functionalization remains largely empirical. We propose a simple but effective design strategy for the organic functionalization of photocathodes for high-efficiency hydrogen generation based on first-principles density functional theory (DFT) calculations. The surface dipole of the functionalized photocathode determines its barrier height, which can be optimized to enhance charge separation at the semiconductor-electrolyte interface. Focusing on p-Si(111) photocathodes functionalized with different mixed aryl/methyl monolayers, we use DFT to systematically investigate the effect of - the presence and distribution of pi bonds, binding atom (the atom in the functional group that bonds with the Si surface), functional group length, and electrophilic substituent groups - on the surface dipole and charge rearrangement at the functionalized surface. We find that the most important factors affecting the surface dipole are the intrinsic molecular dipole moment of the organic moiety, the presence of electrophilic substituent groups, and the binding atom. Using these findings, a three-step design strategy is proposed for the experimental realization of high-performing functionalized p-Si(111) photocathodes by maximizing the surface dipole.

Combining user involvement with innovative design to develop a radical new method for managing N fertilization

In France, a single science-based model has dominated winter wheat N fertilizer management for 40 years. Despite scientific progress, it remains challenging to minimize N losses whilst maximizing grain yield and achieving satisfactory grain protein content. A mismatch between the science-based method and its implementation has been demonstrated. We thought that involving users early in the design process would lead to explore more relevant methods regarding the diversity of N issues and implementation conditions. We used a three-step design process: (1) a diagnosis of the uses of existing methods and tools, (2) a design process combining participatory workshops, generation of new knowledge and model-based prototyping, and (3) a test of the prototype in the users’ conditions. We identified the fixing of a target yield a priori as one of the major problems with the current N fertilization method. We thus established an exploratory conceptual axis: “a fertilization method without target yield”. Design workshops led to a new method based on (1) the regular monitoring of crop N nutrition, (2) the acceptance of periods of crop N deficiency, and (3) the simulation of short-term soil N availability with a crop model. New knowledge was generated, and the Azodyn model was used to build decision rules for N applications, based on viability theory. The prototype was tested by two groups of farmers. We show that, by combining the three steps used here, it was possible to develop an innovative fertilizer method radically different from the dominant paradigm, and positively received by users.

Comprehensive design methodology for control and data planes in wavelength-routed optical networks

We propose a comprehensive design methodology for control and data planes of wavelength-routed optical networks (WRONs) employing mixed-line-rate (MLR) transmission for cost-effective resource provisioning. The proposed approach attempts to minimize the maximum lightpath capacity demand in Gbps (representing the measure of lightpath congestion) in network for a given traffic matrix by using a mix of a heuristic scheme and linear programming (LP). In the first step of the proposed three-step design, some lightpaths are set up on a set of judiciously selected fiber links (with point-to-point lightpaths between neighboring nodes), on a specific wavelength throughout the network, and an appropriate fraction of the same set of lightpaths is utilized for carrying control information, forming therefore the control plane (CP) of the WRON. The remaining bandwidth of these lightpaths is utilized to carry the data traffic along with all other designed lightpaths of the WRON using appropriate algorithm, forming the overall data plane (DP) of the WRON. In the second step, traffic routing is carried out through LP to minimize lightpath congestion in the network. In the third step, we utilize the results of LP to assign rates to lightpaths, such that the cost (considering only the transceiver cost) of the network is minimized. This design leads to congestion-aware MLR network with due consideration to cost-effectiveness without compromising the network restoration response against link failures. We carry out simulation studies employing possible CPs using both symmetric (CP topology being same as the physical topology) as well as asymmetric (using fewer fiber links than the symmetric case) topology. The results of our simulations indicate that the proposed design of CP with symmetric/asymmetric topology and in-band transmission with sub-lightpath capacity can bring down network congestion and cost with respect to symmetric out-of-band transmission (using fully reserved lightpaths for CP), without any perceptible sacrifice in respect of the network restoration time. Failure can occur either in CP or DP, or in both the planes. We investigate the effect of design of CP with symmetric/asymmetric topology on network restoration time for single- and double-link failures. We further present DP design methodology with hybrid restoration scheme, i.e., combination of dedicated (1:1) path protection and path restoration. We analyze the effect of symmetric CP topology and degree of protection on the congestion of the network. Some lightpaths, that support more traffic, are protected against failures, while the others are left for path restoration in the event of failures. As more lightpaths are protected, the congestion and power consumption of network increase. We provide an analysis of the factors that come into play while altering the degree of protection and observe how the choice for the degree of protection in DP can be arrived at using an appropriate design methodology.

Kinetics study of oil extraction from Citrus auranticum L. by solvent-free microwave extraction

Citrus and its oil are of high economic and medicinal value because of their multiple uses, such as in the food industry, cosmetics and folk medicine. The aim of this study is to investigate the potential of solvent-free microwave extraction for the extraction of essential oils from Citrus auranticum L. peels. Specifically, this study verifies the kinetics based on second-order model and mechanism of solvent-free microwave extraction of Citrus auranticum L. peels. Solvent-free microwave extraction is used to extract essential oils from Citrus auranticum L. peels. The initial extraction rate, the extraction capacity and the second-order extraction rate constant were calculated using the model. Using a three-step experimental design of the kinetics of oil extraction from Citrus auranticum L. peels by solvent-free microwave extraction, this study showed that the extraction process was based on the second-order extraction model. The initial extraction rate (h), the extraction capacity (CS), the second-order extraction rate constant (k), and coefficient of determination (R2) was 0.7483 g L-1 min-1, 0.7291 g L-1, 1.4075 L g-1 min-1 and 0.9992, respectively.

From Problem to Solution: Developing a Personalized Smartphone Application for Recreational Runners following a Three-step Design Approach

The aim of this paper is to design and test a smartphone application which supports personalized running experiences for less experienced runners. As a result of a multidisciplinary three-step design approach Inspirun was developed. Inspirun is a personalized running-application for Android smartphones that aims to fill the gap between running on your own (static) schedule, and having a personal trainer that accommodates the schedule to your needs and profile. With the use of GPS and Bluetooth heart rate monitor support, a user's progress gets tracked. The application adjusts the training schedule after each training session, motivating the runner without a real life coach. Results from three user studies are promising; participants were very satisfied with the personalized approach, both in the profiling and de adaptation of their training scheme.

A novel method for fault detection in singularly perturbed systems via the finite frequency strategy

This paper addresses the fault detection synthesis for a class of linear singularly perturbed systems with unknown disturbances. The observer is designed via a novel method, in which singularly perturbed systems could be processed within a uniform framework instead of using the classical slow–fast decomposition. The problem of robust fault detection can be converted into a standard H∞ model-matching. Based on the generalized Kalman–Yakubovich–Popov lemma and parameter-dependent Lyapunov functions, a full-order observer is designed such that the corresponding error dynamic system is asymptotically stable and satisfies a prescribed finite-frequency H_/H∞ performance index. A novel three-step design procedure is then proposed to extract the fault feature from strong background disturbances. An illustrative example is given to demonstrate the validity and applicability of the proposed approaches in the simulation part.

PARS: A scheduling of periodically active rank to optimize power efficiency for main memory

The growing gap between microprocessor speed and DRAM speed is a major problem that computer designers are facing. In order to narrow the gap, main memory is expected to grow significantly in both speed and capacity for it is a major shared resource among cores in a multi-core system, which will lead to increasing power consumption, perhaps replacing the dominant consuming fraction of processor. Therefore, it is critical to address the power issue without seriously decreasing performance in the main memory subsystem. In this paper, we propose a periodically active rank scheduling (PARS) to optimize power efficiency for DRAM in smart phones. Our scheduling features a three-step design. First, we partition all threads in the system into groups. Second, we modify page allocation policy to achieve threads in the same group which occupies the same rank but different banks of DRAM. Finally, we sequentially schedule threads in one group after another while only active running group׳s ranks to retain other ranks low power status. As a result, our scheduling periodically activates one rank after another to optimize memory power efficiency. We implement PARS in Linux 2.6.39 kernel running randomly generated workloads containing single-threaded and multi-threaded benchmark. Experimental results show that PARS can improve both the memory power efficiency by 26.8% and performance by 4.2% average relative to default system while reducing negligible fairness.

Ideal cascade theory applied to carbon monoxide isotope separation by pressure swing adsorption

A three-step design methodology was developed for applying ideal cascade theory to separate a dilute binary gas mixture by pressure swing adsorption (PSA). This methodology was tested via simulation and applied to the enrichment of 14CO from 1 to 20 ppm in a mixture of its own isotopes. It was assumed that the presence and slight enrichment of 13CO did not affect the performance of 14CO throughout the cascade. An 8 stage cascade was analyzed, with 3 stages in the stripping section, 5 stages in the enriching section and the feed fed to stage 4. Each stage consisted of a 3-bed 3-step PSA process of varying size, all utilizing feed pressurization/feed, heavy reflux and countercurrent depressurization steps of equal duration, and the same total cycle time. The performance in terms of overall 14CO recovery from an ideal cascade of PSA units was compared to that from a single PSA unit operating with the same overall 14CO enrichment and same overall throughput as the cascade. The results showed that the cascade of PSA units compared to the single PSA unit exhibited increasingly higher overall recoveries as the overall enrichment decreased; the performance of both systems became identical at an overall enrichment of about 18; and at overall enrichments higher than 18 the single PSA unit exhibited only slightly higher overall recoveries than the cascade of PSA units. The better performing separation process in either case always required more power to operate. In general, this analysis showed how to design an ideal cascade of PSA units for binary isotope separation and that a cascade of PSA units may be more advantageous than a single PSA unit, depending on the desired performance and as long as the capital and operating costs are acceptable.

An Alternating Variable Step-Size Adaptive Long-Range Prediction of LMS Fading Signals

We propose a linear alternating variable step-size adaptive long-range prediction (AVSS-ALRP) scheme to predict fading signals which is especially suitable for a versatile two-state land mobile satellite (LMS) channel model at S-band. A three-step design procedure is presented to optimize the prediction performance. Firstly, we establish the Gilbert-Elliot channel model based on first-order Markov chain for satellite communication downlink and take advantage of smoothing average to obtain channel observed values. At a second stage, eigenvalue decomposition method is applied to predict future long-range channel state instead of weighted prediction. Finally, combining variable step-size least mean squares and adaptive long-range prediction, we introduce the VSS-ALRP algorithm to predict LMS channel fading signals in the case of “ good” state, and the obtained prediction results would be revised based on the linear prediction of error when shadowing condition is in the “ bad” state. Simulation results show that the proposed scheme can not only offer an accurate prediction for long-range channel state and fading signals over the two-state Gilbert-Elliot channel model and greatly enhance the fading signals’ autocorrelation, but also have considerably better performance than long-range prediction (LRP) algorithm from the results of mean square error (MSE) and correlation coefficient.

A three-step design science approach to develop a novel human resource-planning framework in projects: the cases of construction projects in USA, Europe, and Iran

Developing a comprehensive human resource (HR)-planning framework that corresponds to the variety of HR-related issues has seldom been observed in existing project management literature. The present study applies a three-step design science approach to introduce a holistic HR-planning framework. The rigor and relevance cycles in this approach address the HR-related issues in projects and the shortcomings of the literature associated with developing a thorough HR-planning framework. Subsequently, the proposed framework is being validated by an exploratory study undertaken at Parsons Brinckerhoff (USA) and BISOL Group (EU). Next, in line with the guidelines of the design cycle for justifying the use of the framework, a survey is conducted on the collected data from 110 Iranian experts in the construction industry. Using Partial Least Squares for analyzing the data, the outcomes indicate that ‘Empowerment/Training’ could significantly improve the performance of HRs in projects. The results also confirm the substantial impact of ‘Quality Assessment’ on the constructs included the HR-planning framework. Furthermore, ‘Networking Management’, ‘Delegating’, and ‘Reward/Compensation’ are prioritized as the subsequent influential constructs for effective HR management practices.

Coupled simulation of natural ventilation and daylighting for a residential community design

This investigation proposed a three-step design procedure to fully utilize natural ventilation with a performance simulation of daylighting. A residential community in Chongqing, China was taken as an example case to illustrate the design procedure from building level to floor level. The building spacing and orientation was optimized through outdoor velocity and pressure field simulation with computational fluid dynamics method. It was showed that the building pressure difference and unit pressure difference can increase for about 10–30% by changing the spacing and building orientation. With the shading and view shadow effect between buildings considered, a final building layout design was determined for the real terrain. Finally, the indoor air flow distribution and daylighting performance in a standard floor was predicted and optimized by modifying indoor floor planning. The result was used to provide suggestions on window allocation and indoor floor plan. The benefits of indoor air quality and energy consumption from natural ventilation were also discussed for Chongqing, China. A rough estimation showed that the energy saving potential of natural ventilation in Chongqing, China could be up to 40% in terms of electricity consumption.

Study and Application of Three-Step Supporting Design Method in Coal Roadway

Scientific supporting design is of great significance to ensure coal roadway stability. The three-step supporting design method is put forward for coal roadway support: The first step is preliminary design, determine the range of each supporting parameter according to the theoretical calculation and supporting experiences; the second step is numerical simulation calculation, choose the reasonable one through the comparison of schemes; the third step is field monitoring, verify the scheme applicability. After applying the three-step supporting design method to study 3# coal seam roadway in Guandi mine, the optimal supporting scheme is obtained, and good results of underground roadway are achieved, which ensure the stability of roadway surrounding rock. Meanwhile, some rules are summarized which provide references for future roadway supporting design.

Sparse structured non-fragile H ∞ controller design for linear systems

This paper presents a study on the problem of designing non-fragile H∞ controllers with sparse structures for linear continuous-time systems. A new algorithm is proposed to define and further design sparse structured controllers. Firstly, sparse structures are specified from a given fully parameterized H∞ controller. Then, a three-step design procedure for non-fragile dynamic output feedback H∞ controllers with the sparse structures is provided. The resulting designs guarantee that the closed-loop system is asymptotically stable and the H∞ performance from the disturbance to the regulated output is less than a prescribed level. A numerical example is given to illustrate the design methods.

On the Architectural Design of University Libraries

The architectural design of university libraries is a systematic engineering. Based on the analysis of the main factors affecting the design, this thesis puts forward such principles in university library design like "flexibility", "efficiency", "ecology and "humanity" and thus suggests that the library architectural design should follow "three-step design process".

Design and field-scale implementation of an “on site” bioremediation treatment in PAH-polluted soil

An “on site” bioremediation program was designed and implemented in soil polluted with polycyclic aromatic hydrocarbons (PAHs), especially naphthalene. We began by characterizing the soil's physical and chemical properties. A microbiological screening corroborated the presence of microorganisms capable of metabolizing PAHs. We then analyzed the viability of bioremediation by developing laboratory microcosms and pilot scale studies, to optimize the costs and time associated with remediation. The treatment assays were based on different types of biostimulants, such as a slow or fast-release fertilizer, combined with commercial surfactants. Once the feasibility of the biostimulation was confirmed, a real-scale bioremediation program was undertaken in 900 m3 of contaminated soil. The three-step design reduced PAH contamination by 94.4% at the end of treatment (161 days). The decrease in pollutants was concomitant with the selection of autochthonous bacteria capable of degrading PAHs, with Bacillus and Pseudomonas the most abundant genera.

Light Weight Design for a Concept Sports Car Using Composite Material

Light weight design is critical to a sports car. In the study, a prototype of the newly developed modern classical concept sports car was presented. The design process followed the common vehicle design procedure starting from blue print, clay model and then vehicle build. The structure was designed and analyzed using Computer Aided Design (CAD) and Computer Aided Engineering (CAE) tools. A space frame design concept was proposed based on the topology optimization results. Carbon composite material was used for light weight structure design. Three-step design optimization process was proposed to use for the detailed composite vehicle structure design with the consideration of manufacturing constraints. The thickness, fiber orientation and stack sequence were obtained through the optimization process. Manufacturing constraints could be imposed to the optimization process in order to obtain a practical design that could be manufactured. A design with total structure weight of 296.7 kg was obtained. It was a much lighter design compared to the earlier metal structure design.

On Reset Control Systems with Discrete-time Triggering Conditions

AbstractIn reset control systems, reset actions are triggered whenever a continuous signal crosses a hyperplane. In the computer-based implementation, however, the continuous triggering signal is sampled and the triggering condition is replaced by a discrete-time counterpart. In this work, we are interested in stability analysis and design of reset control systems based directly on discrete-time triggering conditions. First of all, a relationship between reset control systems and switched systems is established and some stability criteria are obtained. Secondly, it is revealed that a reset control system can be regarded as a hybrid system combining an underdamped baseline system and an overdamped reset mode. In addition, it is showed by example that the reset matrix, which is assumed to be zero in general, has significant effect on the damping ratio of the reset mode and thus can be adjusted to further improve the performance. Based on this observation, a three-step design procedure is proposed. A hard disk drive example is also investigated to demonstrate the proposed design procedure.

Phase I/II Study of Capecitabine Plus Oxaliplatin (XELOX) Plus Bevacizumab As First-line Therapy in Japanese Patients with Metastatic Colorectal Cancer

ObjectiveThe addition of bevacizumab to fluoropyrimidine-based combination chemotherapy as first-line therapy for metastatic colorectal cancer results in clinically significant improvements in patient outcome. However, clinical trials have been conducted primarily in Caucasian patients with only a small proportion of Asian patients. This Phase I/II study was designed to evaluate the efficacy and safety of XELOX (capecitabine plus oxaliplatin) plus bevacizumab in Japanese patients with metastatic colorectal cancer.MethodsPatients with previously untreated, measurable metastatic colorectal cancer received bevacizumab 7.5 mg/kg and oxaliplatin 130 mg/m2 on day 1, plus capecitabine 1000 mg/m2 twice daily on days 1–14, every 3 weeks. A three-step design evaluated in: step 1, initial safety of XELOX in six patients; step 2, initial safety of XELOX plus bevacizumab in six patients; and step 3, efficacy and safety in a further 48 patients. The primary study endpoints were safety and response rate.ResultsNo dose-limiting toxicity occurred during Steps 1 and 2. Fifty-eight patients were enrolled in Steps 2 and 3 and received XELOX plus bevacizumab. In the 57 patients assessed for response, the overall response rate was 72% (95% confidence interval, 58.5–83.0). Median progression-free survival was 11.0 months (95% confidence interval, 9.6–12.5) and median overall survival was 27.4 months (95% confidence interval, 22.0–not calculated). Eight patients (14%) underwent surgery with curative intent. The most common grade 3/4 adverse events were neurosensory toxicity (17%) and neutropenia (16%).ConclusionsXELOX plus bevacizumab is effective and has a manageable tolerability profile when given to Japanese patients with metastatic colorectal cancer.

Serially concatenated continuous phase modulation for satellite communications

In this paper, serially concatenated continuous phase modulation (SCCPM) is considered for the uplink of satellite communications. A three-step design procedure is proposed to optimize the association of the outer code and the CPM for a wide range of spectral efficiencies, ranging from 0.75 to 2.25 bit/s/Hz. Firstly, EXIT chart analysis is applied to derive general guidelines for choosing SCCPM parameters. A significant result is that a high-rate outer code is required to achieve good convergence threshold, given a spectral efficiency. At a second stage, union bounds to the error probability are considered to choose the outer code under the constraints arising from the EXIT charts analysis. From this analysis, extended BCH codes and extended Hamming codes are proposed as outer code for broadband and narrowband transmission, respectively. For the latter, double-binary convolutional codes and symbol interleaving is also proposed as a valid alternative. Finally, combining both EXIT charts and union bounds we optimize the association of code and CPM to achieve both low error rates and good convergence. The proposed concatenated structure offers very low error floors and good performance in the waterfall region for all considered spectral efficiencies. A significant improvement with respect to previous concatenated CPM schemes is shown.