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Without a reliable and scalable system for managing authorized users and ensuring they receive their allocated share of computational and storage resources, modern HPC centers would not be able to function. Exascale will amplify these demands with greater machine scale, more users, higher job throughput, and ever-increasing need for management insight and automation throughout the HPC environment. When our legacy system reached retirement age, NERSC took the opportunity to design and build Iris not only to meet our current needs, with 8,000 users and tens of thousands of jobs per day, but also to scale well into the exascale era. In this paper, we describe how we have designed Iris to meet these needs and discuss its key features as well as our implementation experience.

Automated parameter search has become a standard method in the modeling of neural systems. These studies could potentially take advantage of recent developments in nonlinear optimization, and the availability of software packages containing high-quality implementations of algorithms that proved useful in other domains. However, a systematic comparison of the available algorithms for problems that are typical in neuroscience has not been performed. We developed a software tool for fitting the parameters of neural models, which provides intuitive, uniform access to a variety of state-of-the-art optimization algorithms implemented by four different Python packages. We also established a set of benchmark problems of different complexity that involve a variety of widely used neuronal models. We then used our optimization tool to systematically evaluate the performance of the algorithms on our set of benchmark problems. We found that several evolutionary and related algorithms consistently provided good solutions for all of our benchmarks. However, the relative performance of the different methods, both in terms of the quality of the final result and in terms of convergence speed, depended substantially on the nature of the problem. We hope that our software tool and benchmarking results will facilitate the choice and application of the best parameter-fitting methods in neuroscientific research.

The North-up reference frame on cartographic maps is a cultural convention that originates in the astronomicalgeometrical worldview of ancient Greek cosmology. Although a relatively young tradition, it had substantial influence on human spatial thinking from the Renaissance. Recent geo-visualization applications may display maps with dynamic, head-up orientation to support turn-by-turn navigation. Increased GPS use seems not to support survey knowledge related to spatial memory. In the current study we tested the sense of North in a sample of young adults. We created an ecologically valid experimental setting and carefully selected a special location at ELTE university campus in Budapest. Standing near river Danube and heading an easterly direction our 36 participants first indicated North in a vista space; then they pointed toward salient urban landmarks in the city. In the second part they marked graphically the directions of important cities in Europe and, finally, they once again indicated the direction of the North in a geographic reference frame. Our results demonstrate that the participants had a clear sense of geographical North, which was not biased by the setting, buildings and available landmark cues. Furthermore, test subjects living longer in Budapest had a better sense of North, supporting a learned component in this directional knowledge. Our experiment in the physical world resulted in supporting evidence that North is still maintained in human cognitive maps as the cardinal direction for orientation.

Current additive technologies enable to produce a new type of components. It is very interesting for technical practice to know their mechanical properties and behavior during an operating mode. The article aims to study Young’s modulus of the simple lattice structures made from plastics using Fused Deposition Modeling technique. Experimental pressure tests were carried out to evaluate Young’s modulus of samples with six different volume ratios of the same porous structure. Five pieces of samples for every volume ratio have been produced from Acrylonitrile Butadiene Styrene (ABS) material. Obtained data were statistically processed and a dependency of Young’s modulus on the volume ratio for selected structure has been plotted and mathematically described. Results showed that it is a strong dependency with an exponential character of the trend curve.

At present, while the development of technology used to display, create, and manipulate 3D models is already very advanced, we are still confronted with situations where it is necessary to use technical documentation. Whatever the production or educational process, this part of the documentation will still be necessary. With this fact, we are increasingly forced to think about how it would facilitate the process of reading and learning with this kind of media. Due to the often inadequate technical level of the interested persons, we come in this article with a way of possible implementation of the augmented reality into the technical documentation, to facilitate its reading and to improve the spatial perception of the included objects.

This article analysis the bidirectional operation of the so called Isolated Efficient Wide Range Converter (I-EWiRaC), equipped with synchronous rectification, including small signal modelling and controller design. The converter is used in fuel-cell-based back-up systems, with ultra capacitors (UC) as intermediated energy storage between the fuel cell and the power converter. Earlier, an additional converter was used to charge the UC to the required DC voltage. The presented idea can improving the system efficiency and reliability and reduce overall system costs.

Major heart rhythm disorders are often treated by implanting a pacemaker, but the pacemaker leads are vulnerable and sometimes need to be replaced. Extraction of malfunctioning leads (wires)is a risky and long procedure, which is currently performed under X-ray guidance. 3D Transesophageal Echocardiography (TEE)can be used as an image guidance tool in order to reduce the radiation dose. However, due to long procedure time there is a need for thinner probes that cause less discomfort to the patient and less image blockage to X-ray. We propose a new 4D reconstruction method from 2D images acquired using a manually rotated microTEE probe. The method uses a normalized convolution approach which adapts its kernel sizes to the local density in the sampling distribution. The method is optimized and tested with 2D ultrasound sequences generated from ground truth 4D datasets with angle/phase sampling distributions from actual micro TEE recordings. The adaptive method outperforms standard NC with respect to RMSE and SSIM measures for a range of distributions.

Proton exchange membrane (PEM) fuel cells are a maturing technology and has in recent years entered the market of backup power systems for e.g. telecommunication applications. Here they provide emission-free and long load support during grid failures and outages. Monitoring performance indicators of PEM fuel cell systems in the field can contribute to improved lifetime, maintenance scheduling and thereby economic competitiveness.This paper establishes some performance indicators and extracts these from a number of sites, that are all installed and operating in the field. The extracted performance indicators include stack operating time, operating time at non-optimum temperature, consumed reactants, voltage decay, and state of health estimation.

Strong-coupling between organic emitters and plasmonic modes supported by multilayers consisting of wavelength-scaled gratings was inspected. Although, the split is larger on the lower branch of originally short-range modes, the modes characteristic on the upper branch of originally long-range modes is more advantageous for applications.

The new VHDL package proposed in this paper makes it possible to perform switch level logical simulation of a wide selection of CMOS circuits, in particular those that utilize the temporary charge storage phenomenon occurring on the MOSFET input capacitance for their operation. In addition to the high impedance value Z, there are 5 various strengths driven values and 3 stored values of equal strength, which are weaker than the driven values. Four MOSFET models (strong-n, strong-p, weak-n and weak-p) are belonging to the package. The paper shows that how the MOSFET models supported by the resolution function use the stored values as ’nut washers’ under the driven values, realizing with this the logical modeling of temporary charge storage. The new package supports the switch level logical simulation of the most versions of CMOS circuits.

The application of current reverse engineering techniques can be integrated into a modern field of tools that support the development of the economy not only in the engineering industry. The main idea of this paper is to diagnose problems with a non-destructive method by use of the created device and reverse engineering tools, to obtain data that will be merged into individual views and obtain a cloud of points transformed into spatial views of hard-to-reach machine part locations.

At present, 3D printing is considered as a new phenomenon of the 21st century. 3D printing is an additive manufacturing technology which can create a physical model of layering material based on electronic data. It is a fast and efficient technology that uses real physical imaging of the exact dimensions of prototype models produced by the gradual application and curing layers of material in the form of foils, powders, wire coils, and the like. The current trend is the continuous development of 3D printing technology in the form of experimentation by using new types of materials and the development of new, specially designed 3D printers and devices that lead to progress in modeling in several areas of industry. By combining several advanced means of technology into one unit an interesting idea to create a device to print larger and more complex shapes of parts may arise. The article describes the design of a 3D print head working with the ABB IRB 140 robotic arm with goal to design a device which is able to print larger objects in size compared to conventional 3D printer.

The use of contemporary reverse engineering techniques may be classified in the modern field of tools which enhance the development of the economy not only in the engineering industry. Nowadays, the producers of reverse engineering devices come up daily with new possibilities of how to significantly reduce the preparation time and rationalize the development process, yet the link between the non-destructive diagnostics and reverse engineering is still not covered. This article considers the aim of creating a device, by integrating a specific software and hardware platform, which will serve to diagnose hard to reach places, and based on data recovered by the technique of laser beam scanning, identify trouble spots and find convenient solutions for creating new components or modifying old ones.

The study of the history of cognitive processes is essential to understand the co-evolution of humans and artefacts. In the current pioneer eye tracking experiment we used a complex and colorful early map as stimulus. We analyzed eye movements of 28 novice map readers. Our results suggests interaction between bottom-up (i.e. visual clutter) and top-down (eccentricity) cognitive processes in viewing patterns. These research findings represent a novel direction in studying the history of cognitive data visualizations and could be considered in directing contemporary design of user interfaces.

These days electrolyzers are becoming more and more interesting due to the high demand for energy storage in form of hydrogen for renewable power generation using fuel cells. The design of a power supply for such a system is complex especially when the DC-link capacitance is reduced. By substituting the complex switching model of the power supply with a simplified one, the system dynamics can be better observed. The resonances caused by the small DC link capacitor and grid side inductance can be easier analyzed. A feed forward compensation method is proposed based on the simplified model of the system in order to minimize the effects of the DC link voltage ripple on the load voltage and current. The proposed method uses Frequency-Locked Loop (FLL) for estimating the fundamental component of the DC-link voltage ripple. Based on the reconstructed rectifier component a new feed-forward compensation signal is created, canceling in such a way the resonance introduced by the grid inductance and the DC-link capacitor from the feed-forward loop. The theoretical work has been validated through experiments on a 5 kW DC power supply used for electrolyser application.

Pulse Width Modulated AC drives equipped with small DC-link capacitor are becoming an attractive solution for electric drive applications with moderate requirements for shaft dynamic performance. However, when these drives are fed from a weak grid a resonance between the line side impedance and the DC-link capacitor appears. Due to this resonance, the THD and the partially weighted harmonic distortion of the line currents are increased, which may rise compatibility problems with the AC line harmonic standards. By using vector control the motor drive is transformed into a constant power load from the DC-link point of view, leading to instability of the entire drive system. This paper proposes a novel DC-link voltage compensation method, which can reduce the amplitude of the above mentioned oscillation, while the large DC-link voltage variation, caused by the rectification can be eliminated from the motor current. The method has been experimentally validated and the results show excellent performance. Moreover, the proposed compensation method can be applied for any kind of load connected to a three-phase passive rectifier equipped with small capacitor.

Cooling high-end system processors has become increasingly more challenging due to the increase in both total power and peak power density in processor cores. Junction peak temperature at worst case corner conditions often establish the limits on the maximum supportable circuit speed as well as processor chip yield. While significant progress has been made in cooling technology (e.g., cold plate design and thermal interface materials at first and the second level package), a systematic approach is needed to optimize the entire thermal and mechanical stack to achieve the overall (optimal) thermal performance objectives. The necessity and importance of this is due to the thermal and mechanical design interdependencies contained with the overall stack. This paper reports an in-depth study of the thermal-mechanical interactions associated with the cold plate, second level thermal interface material (TIM2) and heat spreaders. Thermal test results are reported for different cold plate designs and TIM2 pad sizes. Thermal and mechanical modeling results are provided to quantify the TIM2 thermal performance as a function of the TIM2 mechanical stress, the TIM2 dimensions and cold plate design. As described via both modeling and testing results, an optimal TIM2 pad size results as a trade-off between heat transfer area for conduction and TIM2 compressive pressure. In addition, pressure sensitive film study results are also provided revealing that heat spreader design affects the module level and TIM2 thermal performance. Results from this set of work clearly demonstrate the close interactions between cooling hardware in the stack hence the importance of thermal-mechanical co-design to achieve optimal thermal performance for the high-end processors.

The paper presents a three-phase prototype power supply operated electrolyser system for household hydrogen production and storage systems. The purpose of the work was to increase the overall efficiency of an electrolyser system by improving the performance of the power supply. The new prototype was designed for high efficiency by using SIC MOSFETs and PSFB-CD with slim-DC topology. The advantages of using small DC-link capacitor is the small inrush current and longer lifetime (film capacitors can be applies). As a side effect a 300 Hz ripple is introduced in the output current which according to the measurements and the literature about the previous work does not affect the H2 production. The resulting efficiency of the power supply is 94.3 % at nominal power and does not drop under 90 % even at light loads (>1 kW).

The recent indoor localization techniques use inertial sensors for position estimations in order to obtain a certain degree of freedom from infrastructure based solutions. Unfortunately, this dependency cannot be completely eliminated due to the cumulative errors induced in the localization process. While many methods are designed to reduce the required number of reference points or try to offer unsupervised maintenance, completely infrastructure independent solutions are still missing. In this paper we propose a novel approach for mobile-based indoor localization and navigation services by introducing a context-aware localization framework. We exploit the ability to recognize certain human motion patterns with a smartphone, representing activities related to walking, climbing stairs, taking escalators, etc. This allows the detection of corridors, staircases and escalators, knowledge which can be used to create building interior related reference points. Based on these a scenario specific context interpreter controls the localization process and provides position refinement for the elimination of the cumulated errors. Using our solution the auxiliary reference points can be omitted, thus, a completely infrastructure-free localization system is formed. The proposed solution is evaluated in a subway scenario and its performance is analysed focusing on the influence of dead-reckoning error on path reconstruction, the effect of activity detection quality on localization performance, respectively the benefits of using additional context-related information. The results are promising, our solution presents good localization and path reconstruction performance, showing potential for real-world scenarios, where the deployment of auxiliary localization infrastructure is unfeasible.

The presented OptInv software system provides support for inventory and sales optimization. Generally, small and medium enterprises cannot afford expensive Enterprise Resource Planning (ERP) systems, with effective supply management modules. Supplies are often managed based only on former experience. Inconvenient situations can occur when an order cannot be accomplished because the needed product is missing, or when the money invested in some products becomes a waste. Using the right methods and tools, these problems can be eliminated. The aim of the OptInv project is to provide a Software as a Service (SaaS) solution for this kind of problems. OptInv imports data from accounting software systems and provides statistics about products, providers and sales. Products can be categorized, the value of the stock can be estimated, the consumption can be predicted and in this way the inventory can be optimized.