Gate Library Research Articles

An Algorithm for Reversible Logic Circuit Synthesis Based on Tensor Decomposition

An algorithm for reversible logic synthesis is proposed. The task is, for a given n -bit substitution map, to find a sequence of reversible logic gates that implements the map. The gate library adopted in this work consists of multiple-controlled Toffoli gates with m control bits, where m ∈ {0, …, n − 1}. Controlled gates with large m (> 2) are then further decomposed into smaller gates ( m ≤ 2). A primary goal in designing the algorithm is to reduce the number of Toffoli gates which is known to be universal. The main idea is to view an n -bit substitution map as a rank-2 n tensor, and to transform it such that the resulting map can be written as a tensor product of a rank-(2 n − 2) tensor and the 2 × 2 identity matrix. It can then be seen that the transformed map acts nontrivially on n − 1 bits only, meaning that the map to be synthesized becomes ( n − 1)-bit substitution. This size reduction process is iteratively applied until it reaches a tensor product of only 2 × 2 matrices. The time complexity of the algorithm is exponential in n as most previously known heuristic algorithms for reversible logic synthesis are, but it terminates within reasonable time for not too large n which may find practical uses. As stated earlier, our primary target is to reduce the number of Toffoli gates in the output circuit. Benchmark results show that the algorithm works well for hard benchmark functions, but it does not seem advantageous when the function is structured. As an application, the algorithm is applied to find reversible circuits for cryptographic substitution boxes, which are often required in quantum cryptanalysis.

Discovering quantum circuit components with program synthesis

Despite rapid progress in the field, it is still challenging to discover new ways to leverage quantum computation: all quantum algorithms must be designed by hand, and quantum mechanics is notoriously counterintuitive. In this paper, we study how artificial intelligence, in the form of program synthesis, may help overcome some of these difficulties, by showing how a computer can incrementally learn concepts relevant to quantum circuit synthesis with experience, and reuse them in unseen tasks. In particular, we focus on the decomposition of unitary matrices into quantum circuits, and show how, starting from a set of elementary gates, we can automatically discover a library of useful new composite gates and use them to decompose increasingly complicated unitaries.

Superconducting VLSI Logic Cell Library Using DC-Powered Clockless Dynamic SFQ Gates and ASIC-Style Layout Template

We report a new approach to building an ASIC-style superconducting SFQ logic cell library for the 8-layer 0.35 μm Niobium SFQ5ee process from MIT LL. The developed library layout template supports XY routing with Passive Transmission Lines (PTLs) and targets conventional Place-and-Route assembly for the design of VLSI Random Logic Macros (RLMs). The designed library gates are based on clockless Dynamic SFQ (DSFQ) logic which allows one to directly implement deep combinational logic clouds. The full library gates communicate only via an XY PTL routing plane, while internally they are assembled from smaller self-contained subgates, connected via inductors and placed in one template row. We report test results for two chips that independently verify library subgate assemblies that are used to build DSFQ logic gates as well as active PTL interconnect; on-chip testbenches provide low-speed and high-speed (GHz) test modes. We have achieved low-speed and high-speed functionality of both the DSFQ logic gates (AND, OR, and AO21) and active interconnect circuitry (transmitters Tx and receivers Rx) used for communicating SFQ signals over 700 μm PTLs and short (∼50 μm) series inductor-resistor (LR) connections. The measured speed of the OR and AND logic circuits exceeded 10 GHz, while the speed for PTLs and LR connections was more than 10 and 30 GHz, respectively.

Reducing CNOT count in quantum Fourier transform for the linear nearest-neighbor architecture

Physical limitations of quantum hardware often necessitate nearest-neighbor (NN) architecture. When synthesizing quantum circuits using the basic gate library, which consists of CNOT and single-qubit gates, CNOT gates are required to convert a quantum circuit into one suitable for an NN architecture. In the basic gate library, CNOT gates are considered the primary cost of quantum circuits due to their higher error rates and longer execution times compared to single-qubit gates. In this paper, we propose a new linear NN (LNN) circuit design for quantum Fourier transform (QFT), one of the most versatile subroutines in quantum algorithms. Our LNN QFT circuit has only about 40% of the number of CNOT gates compared to previously known LNN QFT circuits. Subsequently, we input both our QFT circuits and conventional QFT circuits into the Qiskit transpiler to construct QFTs on IBM quantum computers, which necessitate NN architectures. Consequently, our QFT circuits demonstrate a substantial advantage over conventional QFT circuits in terms of the number of CNOT gates. This outcome implies that the proposed LNN QFT circuit design could serve as a novel foundation for developing QFT circuits implemented in quantum hardware that demands NN architecture.

Quantum Computer-Aided Design Automation

Quantum computing is an essential issue for taking advantage of quantum properties in real-world applications. Realizing quantum computing with a corresponding quantum circuit is a critical step. This study introduces the AngelQ system, which provides quantum computing-as-a-service (QCaaS) for the cloud. The AngelQ system integrates quantum design automation (QDA) to achieve quantum and reversible circuit synthesis by a quantum-inspired optimization (QiO) technique and has visualization software interfaces to verify the QiO process and the correctness of the synthesized quantum and reversible circuits. First, the proposed novel QiO method has four significant features: Adaptive strategy, quantum-Not gate, update mechanism by Global solutions, and Entanglement Local search, named Angel QiO. which is a flexible technique to realize various circuits under different gate libraries with a few alterations. Angel QiO can construct diversified function-equivalent circuits to assess the circuit composition and boost the development of circuit synthesis. Second, researchers can observe the QiO algorithm process and inspect the intermediate result formula through AngelQ system’s visualization interface to further adjust the parameters and improve the performance. Moreover, it benefits beginners’ learning and adds convenience to education. In summary, the AngelQ system can extend and facilitate the future design and automation of quantum computing.

Three-Input NPN Class Gate Library for Atomic Silicon Quantum Dots

This article proposes a complete three-input gate library using atomic silicon quantum dots made of silicon dangling bonds.

Designing an open-source application to record library gate counts in response to COVID-19

In response to the COVID-19 pandemic, the Oklahoma State University Library developed an open-source application to record real-time building capacity. Library student security tracks building entrances and exits via the program, with current visitor numbers appearing on the library’s website via an API. This effort helps administrators have a clear picture of building capacity during opening hours for data-driven decision-making and provides users information regarding the library’s level of activity.

Tuberculin skin tests following Bacille Calmette Guerin vaccination in Africa: a protocol for systematic review and meta-analysis.

Tuberculin reactivity following tuberculin skin test which is the most common measure of the effect of the Bacille Calmette Guerin (BCG) vaccination has remained complex. This protocol is aimed to assess the effect of BCG vaccine on tuberculin skin test in Africa as a guide to better understanding or resolving this complexity. A search strategy is developed using MeSH, key words, text words, and entry terms. Five databases will be searched, including PubMed, African Journals Online (AJOL), Google Scholar, Research Gate, and Cochrane Library. Only observational studies conducted in Sub-Saharan Africa and retrievable in English language will be included. The primary measurable outcome of this study is pooled prevalence of positive tuberculin skin tests. Secondary outcomes are factors that influence Tuberculin Skin Test (TST) positivity such as BCG type, the dose of BCG, age at BCG vaccinates, time/interval between BCG vaccination and TST, and type of tuberculin unit used for TST. Identified studies will be screened and selected based on inclusion criteria. Data will be extracted into Zotero, Microsoft Excel and CMA software. Both quality scores and the risk of bias for individual studies will be reported. Studies will be assessed for methodological, clinical, and statistical heterogeneity. Funnel Plots will be used for assessing publication bias. The results will be presented in tabular format in addition to a narrative synthesis. The pooled prevalence of effect of BCG vaccine on TST in Africa will be examined in relation to factors that influence TST positivity.

Automated Design of Robust Genetic Circuits: Structural Variants and Parameter Uncertainty.

Genetic design automation methods for combinational circuits often rely on standard algorithms from electronic design automation in their circuit synthesis and technology mapping. However, those algorithms are domain-specific and are hence often not directly suitable for the biological context. In this work we identify aspects of those algorithms that require domain-adaptation. We first demonstrate that enumerating structural variants for a given Boolean specification allows us to find better performing circuits and that stochastic gate assignment methods need to be properly adjusted in order to find the best assignment. Second, we present a general circuit scoring scheme that accounts for the limited accuracy of biological device models including the variability across cells and show that circuits selected according to this score exhibit higher robustness with respect to parametric variations. If gate characteristics in a library are just given in terms of intervals, we provide means to efficiently propagate signals through such a circuit and compute corresponding scores. We demonstrate the novel design approach using the Cello gate library and 33 logic functions that were synthesized and implemented in vivo recently (Nielsen, A., et al., Science, 2016, 352 (6281), DOI: 10.1126/science.aac7341). Across this set of functions, 32 of them can be improved by simply considering structural variants yielding performance gains of up to 7.9-fold, whereas 22 of them can be improved with gains up to 26-fold when selecting circuits according to the novel robustness score. We furthermore report on the synergistic combination of the two proposed improvements.

Area efficient camouflaging technique for securing IC reverse engineering.

Reverse engineering is a burning issue in Integrated Circuit (IC) design and manufacturing. In the semiconductor industry, it results in a revenue loss of billions of dollars every year. In this work, an area efficient, high-performance IC camouflaging technique is proposed at the physical design level to combat the integrated circuit's reverse engineering. An attacker may not identify various logic gates in the layout due to similar image output. In addition, a dummy or true contact-based technique is implemented for optimum outcomes. A library of gates is proposed that contains the various camouflaged primitive gates developed by a combination of using the metal routing technique along with the dummy contact technique. This work shows the superiority of the proposed technique's performance matrix with those of existing works regarding resource burden, area, and delay. The proposed library is expected to make open source to help ASIC designers secure IC design and save colossal revenue loss.

Impact of COVID-19 on the use of the academic library

PurposeThis study examines differences in library use patterns (in-person visits, online use, reference transactions, library resource and services use) pre-COVID-19 and during the COVID-19 pandemic through multiple data sets.Design/methodology/approachUsing library statistics collected during 2017/2018 and 2020/2021 and student responses to a biennial library use survey distributed in 2018 and 2021, the potential impact of the pandemic on users' behaviors was explored.FindingsLibrary use statistics and the biennial survey responses demonstrate that users' overall library use was impacted by COVID-19. Both the library's gate count and students' frequency of library visits showed a dramatic decrease. The use of virtual support to patrons increased during COVID-19 as reflected by the increase in email and chat reference interactions and virtual consultations.Practical implicationsAs students return to the physical classroom, observing library use via various data will help inform how well use of the library rebounded or if there are changes in users' behavior that suggest the need for the promotion of library services or an expansion in alternative services to support users.Originality/valueThis article highlights the importance of continuously obtaining various data sets to observe trends and changes. By observing multiple data points, some changes are aligned across data, whereas other changes or patterns are different. While impact on physical library use may be obvious, library use before and during the pandemic will help guide and inform how academic libraries should be prepared for hybrid environments post-pandemic.

Efficient Designs of Quantum Adder/Subtractor Using Universal Reversible Gate on IBM Q

Reversible arithmetic and logic unit (ALU) is a necessary part of quantum computing. In this work, we present improved designs of reversible half and full addition and subtraction circuits. The proposed designs are based on a universal one type gate (G gate library). The G gate library can generate all possible permutations of the symmetric group. The presented designs are multi-function circuits that are capable of performing additional logical operations. We achieve a reduction in the quantum cost, gate count, number of constant inputs, and delay with zero garbage, compared to relevant results obtained by others. The experimental results using IBM Quantum Experience (IBM Q) illustrate the success probability of the proposed designs.

Automated design and implementation of a NOR gate in Pseudomonas putida.

Boolean NOR gates have been widely implemented in Escherichia coli as transcriptional regulatory devices for building complex genetic circuits. Yet, their portability to other bacterial hosts/chassis is generally hampered by frequent changes in the parameters of the INPUT/OUTPUT response functions brought about by new genetic and biochemical contexts. Here, we have used the circuit design tool CELLO for assembling a NOR gate in the soil bacterium and the metabolic engineering platform Pseudomonas putida with components tailored for E. coli. To this end, we capitalized on the functional parameters of 20 genetic inverters for each host and the resulting compatibility between NOT pairs. Moreover, we added to the gate library three inducible promoters that are specific to P. putida, thus expanding cross-platform assembly options. While the number of potential connectable inverters decreased drastically when moving the library from E. coli to P. putida, the CELLO software was still able to find an effective NOR gate in the new chassis. The automated generation of the corresponding DNA sequence and in vivo experimental verification accredited that some genetic modules initially optimized for E. coli can indeed be reused to deliver NOR logic in P. putida as well. Furthermore, the results highlight the value of creating host-specific collections of well-characterized regulatory inverters for the quick assembly of genetic circuits to meet complex specifications.

Synthesis Strategy of Reversible Circuits on DNA Computers

DNA computers and quantum computers are gaining attention as alternatives to classical digital computers. DNA is a biological material that can be reprogrammed to perform computing functions. Quantum computing performs reversible computations by nature based on the laws of quantum mechanics. In this paper, DNA computing and reversible computing are combined to propose novel theoretical methods to implement reversible gates and circuits in DNA computers based on strand displacement reactions, since the advantages of reversible logic gates can be exploited to improve the capabilities and functionalities of DNA computers. This paper also proposes a novel universal reversible gate library (URGL) for synthesizing n-bit reversible circuits using DNA to reduce the average length and cost of the constructed circuits when compared with previous methods. Each n-bit URGL contains building blocks to generate all possible permutations of a symmetric group of degree n. Our proposed group (URGL) in the paper is a permutation group. The proposed implementation methods will improve the efficiency of DNA computer computations as the results of DNA implementations are better in terms of quantum cost, DNA cost, and circuit length.

Gate register tool with koha library automation software

The article presents an attempt to integrate gate registerwith open-source software Koha Integrated Library Management System. Using this option, the patron's library card will be scanned by the system during entry and exit at the library gate, and this information will be storedin the new table which we have added to the Koha database. Using this tool various reports can be generated for various library management purposes. In the final phase, we have developed a patch for Koha which has enabled the users of the library to update their profile in Koha without library staff help. This tiny addition to Koha has enabled it toward crowdsourcing mode. The above two tools are tested in the real-time environment and positive feedback has been reeived from library staff and users.

Single-bit comparator in quantum-dot cellular automata (QCA) technology using novel QCA-XNOR gates

To fill the continuous needs for faster processing elements with less power consumption causes large pressure on the complementary metal oxide semiconductor (CMOS) technology developers. The scaling scenario is not an option nowadays and other technologies need to be investigated. The quantum-dot cellular automata (QCA) technology is one of the important emerging nanotechnologies that have attracted much researchers’ attention in recent years. This technology has many interesting features, such as high speed, low power consumption, and small size. These features make it an appropriate alternative to the CMOS technique. This paper suggests three novel structures of XNOR gates in the QCA technology. The presented structures do not follow the conventional approaches to the logic gates design but depend on the inherent capabilities of the new technology. The proposed structures are used as the main building blocks for a single-bit comparator. The resulted circuits are simulated for the verification purpose and then compared with existing counterparts in the literature. The comparison results are encouraging to append the proposed structures to the library of QCA gates.

Assessment on a Dime: Low Cost User Data Collection for Assessment

Abstract Objective – This article describes the construction and use of a low cost tool for capturing user demographics in a physical library. Methods – At the Health Sciences Library of Columbia University Irving Medical Center, we created the Tap In/Tap Out tool to learn about the demographic details of our library visitors, such as their status, school affiliation, and department. The Tap In/Tap Out tool was implemented twice for two weeks in 2013 and 2017, with users voluntarily tapping their campus ID when entering and leaving the library. We checked campus ID numbers against university databases to fill in demographic details of the library users. Results – We constructed the Tap In/Tap Out tool using a Raspberry Pi and RFID card readers mounted on a foam board poster and placed near the library entrance. Participation in the Tap In/Tap Out tool ranged from 5-7% of the library gate count numbers during the survey periods. Though low, this participation provided a useful indication of user demographics that helped to strengthen library discussions with university administration. The 2013 survey results, which showed that the library space was actively used by students from all the constituent Medical Center schools, were used to support funding justifications. The 2017 survey results, which showed continued library usage, were used to illustrate the value of the library to the Medical Center community. Conclusion – The Tap In/Tap Out tool was inexpensive to implement and provided more information about library visitors than gate counts alone. Findings from the Tap In/Tap Out results were used to demonstrate library usage and justify funding. We describe how other libraries might create and implement the tool to capture greater levels of detail about the users visiting their spaces.

Advanced exact synthesis of Clifford+T circuits

Quantum systems provide a new way of conducting computations based on the so-called qubits. Due to the potential for significant speed-ups, this field received significant research attention in recent years. The Clifford+T library is a very promising and popular gate library for these kinds of computations. Unlike other libraries considered so far, it consists of only a small number of gates for all of which robust, fault-tolerant realizations are known for many technologies that seem to be promising for large-scale quantum computing. As a consequence, (logic) synthesis of Clifford+T quantum circuits became an important research problem. However, previous work in this area has several drawbacks: Corresponding approaches are either only applicable to very small quantum systems or lead to circuits that are far from being optimal. The latter is mainly caused by the fact that current synthesis realizes the desired circuit by a local, i.e., column-wise, consideration of the underlying unitary transformation matrix to be synthesized. In this paper, we analyze the conceptual drawbacks of this approach and propose to overcome them by taking a global view of the matrices and perform a separation of concerns regarding individual synthesis steps. We precisely describe a corresponding algorithm as well as its efficient implementation on top of decision diagrams. Experimental results confirm the resulting benefits and show improvements of up to several orders of magnitudes in costs compared to previous work.

МЕТОДИКА ВИЗНАЧЕННЯ ФУНКЦІОНАЛЬНОГО КЛАСУ ХВОРОГО НА СИСТЕМНИЙ ЧЕРВОНИЙ ВОВЧАК

The correct and comprehensive assessment of the condition of patients with systemic lupus erythematosus and typical SLE-related multi-organ and multisystemic lesions requires developing a new integrated measure of their condition. Such measure should take into account modern advances in understanding the causes and pathogenesis of the disease, while assessing the degree of its activity, its progression, the number and severity of syntropic comorbid lesions of organs and systems, and formulating a clinical diagnosis.Objective. To develop the method of assigning functional classes to patients with systemic lupus erythematosus.Materials and methods. The research was conducted in three successive steps: the purpose of the first step was toconduct a review of literature, i.e. to analyze retrospectively 130 sources of literature in English and Ukrainian using content analysis, systemic and comparative analysis, bibliographic analysis of relevant publications on SLE grading, especially by its severity, in PubMed, Medline, Cochrane Library, and Research Gate databases. The purpose of the second step was to develop a method of assigning functional classes to patients with SLE based on modern literature and our own clinical experience. The purpose of the third step was to demonstrate examples of its application.Results and discussion. There is an obvious need to assess SLE activity, its progression, the number and severity of syntropic comorbid lesions of organs and systems, formulate a clinical diagnosis and assign functional classes to patients with SLE based on easily calculated integrated measures for each patient. However, the review of the literature showed that such a measure had not been developed yet. The proposed method includes three phases. The purpose of the first phase is to assess the activity of systemic lupus erythematosus according to the SELENA-SLEDAI total outcome and assign the appropriate number of points: inactive systemic lupus erythematosus - 0 points, the mild activity of SLE – 1 point, the moderate activity of SLE – 2 points, the high activity and very high activity of SLE - 3 points. The purpose of the second phase is to assess the progression of systemic lupus erythematosus and assign the appropriate number of points: patients with chronic SLE – 1 point, patients with subacute SLE – 2 points, patients with acute SLE – 3 points. The purpose of the third phase was to assess the syntropic comorbid lesions of organs and systems and assign the appropriate number of points: no lesions – 0 points, a slight deviation from normality that does not require treatment – 1 point; lesions that require medical correction – 2 points; severe organ failure that requires immediate treatment – 3 points. The number of points (total score) that can be assigned to a patient with systemic lupus erythematosus ranges from 0 to 45. If the total score is 0, then the patient should be classified as being in remission. If the total score ranges from 1 to 15 points, then the patient should be classified as being in functional class I (the condition of the patient with SLE should be graded as mild). If the total score ranges from 16 to 26 points, then the patient should be classified as being in functional class II (the condition of the patient with SLE should be graded as moderate).If the total score ranges from 27 to 45 points, then the patient should be classified as being in functional class III (the condition of the patient with SLE should be graded as severe). This method takes into account the disease activity, its progression, the number and severity of syntropic comorbid lesions of organs and systems. The total score interpreted according to the defined ranges allows us to assess the condition of patients with SLE in general, i.e. to assign functional classes to them, objectivize expert assessments, determine the dynamics of disease progression and the effectiveness of treatment.Conclusions. We have developed the method to assess the condition of patients with systemic lupus erythematosus in a simple and objective manner by calculating integrated measure that denotes the functional class of patient with SLE. This method takes into account the results of other research studies published in scientific Ukrainian and foreign journals, as well as the results of our research studies. It takes into account the disease activity, its progression, the number and severity of syntropic comorbid lesions of organs and systems. The method can be successfully applied in clinical practice to optimize expert assessments of patient condition, to analyze the dynamics of disease progression and the effectiveness of treatment.

Read in or check out: A four-year analysis of circulation and in-house use of print books

As libraries offer more multi-dimensional study areas and online resources, it is important to understand how print books are being used. The reported decline in print book circulation has largely been based on books checked out of the library without recording in-house use (books used in the library but not checked out). Including in-house use gives a more accurate representation of book circulation, helping to demonstrate the value of the physical library and print collections, and informing collection development. To better understand how our print collections are being used, we analyze holdings, checkout data, and in-house use data by subject, as well as circulation in regard to patron group, library gate count and student enrollment. Our findings show declining use of all print collections with the steepest decline in reference books. The majority of books used in house were not checked out, affirming the need to include in-house use data to provide an accurate picture of print book use and inform collection development. We use our findings to inform the redesign of our reference collection and suggest ways to integrate print and digital formats and promote the value of books and reading.