Partial Evaluation Research Articles

Control-Flow Refinement by Partial Evaluation, and its Application to Termination and Cost Analysis

AbstractControl-flow refinement refers to program transformations whose purpose is to make implicit control-flow explicit, and is used in the context of program analysis to increase precision. Several techniques have been suggested for different programming models, typically tailored to improving precision for a particular analysis. In this paper we explore the use of partial evaluation of Horn clauses as a general-purpose technique for control-flow refinement for integer transitions systems. These are control-flow graphs where edges are annotated with linear constraints describing transitions between corresponding nodes, and they are used in many program analysis tools. Using partial evaluation for control-flow refinement has the clear advantage over other approaches in that soundness follows from the general properties of partial evaluation; in particular, properties such as termination and complexity are preserved. We use a partial evaluation algorithm incorporating property-based abstraction, and show how the right choice of properties allows us to prove termination and to infer complexity of challenging programs that cannot be handled by state-of-the-art tools. We report on the integration of the technique in a termination analyzer, and its use as a preprocessing step for several cost analyzers.

Application of Mathematical Modelling for Optimization of Land-Use Management

Abstract The work has approved the methods of partial economic evaluation of lands by the indicators of yield capacity of agricultural crops, payback of expenditures and differential income for a typical agricultural enterprise, located on the territory of the natural-agricultural province of the Western Forest-steppe. The research supplies proposals concerning improvement of the methods of economic evaluation of lands in Ukraine on the example of the indicators of economic evaluation of the land use at the farming enterprise “GREEN GARDEN”. The indicators are used for the growing of agricultural crops, planning their yield capacity, comparison of the economic fertility of soils and determination of the economic results of growing agricultural crops under the current production conditions in a defined working area. The research proposes the optimization of land-use management, applying a metrical game on the basis of indicators of the economic evaluation of lands to define the optimal share of agricultural crops in crop rotation. This method can be used to optimize land use in any region. Application of mathematical modeling by indicators of differential income ensures that maximum gross income is obtained under the mixed strategy of the game on better and worse soils in the enterprise.

What understanding of economics do medical students have?

Introduction: Economic topics appear in the medical studies curriculum at different times. Despite socio-political relevance, there is hardly any information about the degree of understanding that medical students have of “economics in medicine”. The present study addresses the questions: What understanding of “economics in medicine” do medical students have before the start of the Practical Year? To what extent is economic teaching content understood as “economization” from outside the profession?Method: Magdeburg medical students in the 5th year of study, who participated in preparatory seminars for the Practical Year (PY) in 2014 and 2015 (60 participants each), assessed the relevance of various seminar topics four months prior to the start of the semester. On the basis of a three-stage qualitative-reconstructive partial evaluation, students’ economic understanding is explored through secondary analysis: deductive derivation of the analysis units; integrative basic method (“segmentation”, “micro-linguistic detailed analysis”, “central theme”); development of a theoretical model by placing the central themes in context following Grounded Theory. Results: Based on the theory, 19 free-text answers with economic reference were identified from the total of all free-text answers. Each answer was assigned to at least one of a total of six themes of the students’ understanding of economics: de-professionalizing economization, deciding and working economically, ambivalent requirements for efficiency and equity, the doctor as an entrepreneur, economics as relevant learning content, PY as a conflict-laden setting for economized working and learning. The theoretical model contains social, praxeological and professional references, which can themselves be ambivalent and conflicting.Conclusion: Despite their critical attitude, the surveyed medical students are neither hostile to economics nor do they regard economics in medicine as a taboo subject. Economic learning content is recognized as relevant. Educational formats that tackle the tension between patient and system orientation in a problem-oriented manner can be a productive setting for economic reflection.

Robustness assessment in computer-assisted liquid chromatography procedures based on desirability functions

A novel approach based on the use of desirability functions is presented for the robustness assessment of liquid chromatographic separations as derived from computer-assisted methods development processes. The approach is based on generally accepted hypothesis that a robust separation procedure will be inert to small random variations of the operational variables, typically encountered in the day-to-day routine analytical practice. This means that peak positions along the chromatograms must keep standstill or move insignificantly when operational variables are not intentionally changed. Thus, the degree of peak positions variation as evaluated from mathematical retention models can be used to assess the robustness of the developed procedures before testing the actual performance experimentally. In the approach proposed, this assessment is obtained by fixing a bilateral partial desirability window around each peak in the simulated chromatogram. The whole chromatogram robustness is characterized by an overall desirability value calculated as the geometric mean of the partial desirability windows evaluation. An added advantage of this approach is that the robustness value calculated is normalized between zero and one and thus, easy to interpret. Thus, when chromatograms are simulated and small random variations are introduced into the operational factors of the model, values for the overall desirability close to one means that the procedure performs robustly. On the contrary, low values for the overall desirability clearly indicated a serious lack of robustness. When used in conjunction with the Pareto optimality approach, as shown here, this robustness assessment strategy allows testing several Pareto front solutions before the final experimental testing which is always needed. In this way, a dramatical reduction of the experimental effort is obtained. Although the approach is theoretically applicable to any chromatographic separation, examples of reversed phase liquid chromatographic procedures are used to show the performance of the proposed methodology.

Evaluating transformation progress of historically disadvantaged South Africans: Programme perspective on the downstream petroleum industry

Background: Since the dawn of democracy in 1994, the South African (SA) government has sought to ensure economic transformation of historically disadvantaged people, using a series of programmes and projects. The petroleum downstream of SA, regulated by the Department of Energy, is among the industries that government uses to maximise transformation. Through a licensing sub-programme, one major condition stipulated prior to awarding licences to operate is the inclusion of historically disadvantaged South Africans in the business plans.Objectives: This article evaluates the extent to which one of the sub-programmes developed to empower historically disadvantaged South Africans (HDSA) in the downstream petroleum industry (petroleum licensing) meets the requirements of the identified relevant evaluation criteria, based on the guidelines of the Development Assistance Committee of the Organisation for Economic Cooperation and Development (DAC/OECD).Method: This sub-programme (partial summative evaluation) is critical as it sought to determine its alignment to the tenets of government policy of addressing past inequity by means of economic ownership. The DAC/OECD evaluation criteria were selected to measure the relevance, effectiveness, efficiency, impact and sustainability of the sub-programme. The justification for using this model is that it is appropriate to public policy response and management tool, especially for developing countries. Some of these measurements were conducted qualitatively, while some were done quantitatively.Results: Emerging data trends analysed indicate that there is a great deal of efficiency in the delivery of licences to operate in the downstream petroleum sector as these were issued in high volumes. The same cannot be said about the HDSAs’ economic empowerment, by means of ‘dealer’ and ‘company’ ownership.Conclusion: Research concludes that the lack of critical resources, such as funding, land, infrastructure and critical skills, were the main reasons why the sub-programme is DAC/OECD non-compliant.

Impact of Photochemical Reactions Induced by UV Light in Pterygium Lesions

Pterygium is a frequent ocular disease whose etiopathology is not completely known. Several factors are considered involved in pterygium formation and progression, among which light exposure, age, dry eyes condition, bacterial infections or genetic predisposition. The purpose of our study was to perform a partial evaluation of the social history of 118 patients with pterygium. All of them presented lesions of various sizes, unilateral or bilateral, and underwent surgical removal. We have analysed potential correlations between the degree of progression (lesion size expressed in mm, measured before removal) and several factors: age, sex, residence, sun exposure, presence of chemical burns, smoking habits. According to our results, UV radiation was identified as an important factor, as patients with prolonged exposure exhibited larger lesions. Other factors presented less significant correlations with the size of pterygium lesions.

Postbreast Cancer Surgery Outpatient Rehabilitation Program

Context: Approximately 600,000 new cases of cancer are estimated to occur in Brazil over the 2-year period of 2018–2019, and the world economic impact of cancer was $895 billion dollars in 2008. Aims: To perform an analysis contemplating the clinical profile, impact, and direct medical costs of an outpatient rehabilitation program for patients who have undergone breast cancer surgery. Settings and Design: A partial economic analysis was performed from the perspective of a Brazilian public hospital. Subjects and Methods: An observational study was conducted using data from a retrospective cohort of patients who had undergone breast cancer surgery. These patients had their first rehabilitation appointment between August 2015 and July 2016. Statistical Analysis Used: Pearson's Chi-square test or Fisher's exact test, Student's t-test, Fisher's F-test analysis of variance, or the nonparametric Kruskal–Wallis test. Post hoc tests were conducted to check for differences between the pairs of categories. The nonparametric Kolmogorov–Smirnov test evaluated the data normality. All hypothesis testing used a significance level of 5%. Results: A total of 132 patients underwent the referred rehabilitation program. The goal of total rehabilitation was achieved in approximately 70% of cases. There was improvement in patients' quality of life in most Short-Form Health Survey-36 dimensions. The program's direct cost had an overall median per patient of R$ 7235.32. Conclusions: The study found good results in the indicators of clinical outcome and quality of life. The costs were reported from a partial evaluation point of view and may contribute to future full evaluations.

Social interactions in voting behavior: Evidence from india

We study how voters’ turnout decisions affect the turnout decisions of other voters by exploiting the unique staggered nature of India’s elections. Voting takes places in several phases, with constituencies quasi-randomly assigned to phases. At the time that later phases vote, turnout in earlier phases is public knowledge but results are not. Using an instrumental variables strategy, we find that a 1 percentage point (pp) increase in turnout in the previous phase depresses turnout in the current phase by around 0.38 pp. Falsification tests examining the effect on turnout, of either constituencies in the same phase or in future phases in the same election, produce no effect. Our results are broadly consistent with pivotal voter and ethical voter models, and suggest that partial equilibrium evaluations of turnout interventions may overstate general equilibrium effects.

Economic Impact of Etanercept in Patients with Psoriasis and Psoriatic Arthritis in Spain: A Systematic Review.

IntroductionEtanercept (ETN), a highly effective biological agent for the treatment of psoriasis (PSO) and psoriatic arthritis (PsA), is widely used in Spain. However, evidence of its economic impact is limited, indicating the need for a systematic review of the economic assessments conducted on the use of ETN in the treatment of both PSO and PsA in Spain.MethodsA systematic review was carried out in PubMed, Embase, Cochrane Library, Health Technology Assessment reports and not indexed sources up to November 2018. The inclusion criteria were economic evaluations (total and partial) and dose optimization studies published in English or Spanish on the use of ETN to treat PSO and PsA for ETN in Spain.ResultsA total of 402 publications were identified, of which 32 were selected for inclusion in the review; of these 32 publications, 81.3% analyzed PSO (14 full economic evaluations, 5 partial economic evaluations and 7 dose optimization studies) and 18.8% analyzed PsA (1 economic analysis and 5 dose optimization studies). The perspective of the Spanish National Health Service (NHS) was used in 90.0% (n = 18) of the full and partial economic evaluations. The time horizons ranged from 12 weeks to 2 years. Reductions in the Psoriasis Area and Severity Index (PASI) of 50, 75 and 90% (PASI 50, 75 and 90, respectively) were most commonly used as efficacy outcomes in the complete evaluations. The economic impact of ETN ranged from €9110–14,337/PASI 75 at 12 weeks (50 mg/week) to €82,279/PASI 90 at 2 years, depending on the health outcome, time horizon and ETN dose used. Only one study determined the cost of using ETN for the treatment of PSO (€29,430–52,367/QALY for dose 2 × 25 mg/week or 50 mg/week, respectively). Only one partial economic evaluation on PSA was identified (NHS perspective), resulting in an ETN annual cost of €8585/patient-year.ConclusionConsistent evidence on the economic impact of ETN for the treatment of PSO and PSA in Spain is lacking, mainly due to the highly heterogeneous methodology used and the broad range of outcomes found in the economic evaluations published to date.FundingPfizer S.L.U.Electronic supplementary materialThe online version of this article (10.1007/s13555-019-0301-6) contains supplementary material, which is available to authorized users.

Cost and cost-effectiveness of mHealth interventions for the prevention and control of type 2 diabetes mellitus: a protocol for a systematic review

IntroductionType 2 diabetes mellitus (T2DM) remains one of the most common chronic diseases of adulthood which creates high degrees of morbidity and mortality worldwide. The incidence of T2DM continues to...

Impact of personal bias on performance of employees in public sector banks

PurposeThis study discusses the multitude of challenges that employees in public sector banks face regarding their annual performance appraisal due to personal bias exercised by their supervisors.Design/methodology/approachData were collected by interviewing 50 people working in five leading public sector banks in Pakistan to draw the outcomes of the present research.FindingsProblems lie in the implementation and justification of evaluation policies that affect employees' career growth, progression, and monetary rewards and fringes, which ultimately hit employees' annual performance appraisal. This study evidences the record deterioration in progression of employees due to personal bias as the appraisers give partial evaluations to those with whom they have any differences and favor their nears and dears or those who are more visible to them or remained in their good books due to personal reasons. This leads employees to feel unfairly treated because the evaluation criterion for performance appraisal seems unjust and illogical. This develops despair, distress, hostility, and distrust among employees when the appraisals are being conducted. The appraisal system does not differentiate between performers or nonperformers due to biased evaluations; therefore, decisions on promotions or career progression cannot be based on such appraisals. The problem of demotivation among employees is also a result of an ineffective performance appraisal mechanism, as no differentiation exists between star performers and nonperformers.Practical implicationsWhile considering the prevalent biased evaluation patterns in public sector banks, requisite changes in appraisal design need to be contemplated to rectify the process of performance appraisal and cope with employees' despair, hostility, and distrust.Originality/valueThe paper is an early attempt to investigate impact of supervisors' personal bias on employees' performance management, growth, and progression in public sector banks.

Key regression from constrained pseudorandom functions

Key regression is a primitive that allows a content publisher to give a small amount of keying material, for time stamp i, to a party such that they can derive key ki and all keys kj for time stamps j<i, but not for time stamps j>i. Existing key-regression schemes based on random oracles, pseudorandom permutations, and pseudorandom generators require a publisher to maintain state of size linear in the number of potential keys. In previous work, constant sized publisher state has only been accessible through the use of trapdoor permutations (e.g., RSA). This paper presents a novel key-regression scheme where the publisher must store only a constant amount of state information without trapdoor permutations. This is achieved through the use of constrained pseudorandom functions, a primitive that allows for the delegation of partial evaluation without revealing the key.

Three biomarker tests to help diagnose preterm labour: a systematic review and economic evaluation.

Preterm birth may result in short- and long-term health problems for the child. Accurate diagnoses of preterm births could prevent unnecessary (or ensure appropriate) admissions into hospitals or transfers to specialist units. The purpose of this report is to assess the test accuracy, clinical effectiveness and cost-effectiveness of the diagnostic tests PartoSure™ (Parsagen Diagnostics Inc., Boston, MA, USA), Actim® Partus (Medix Biochemica, Espoo, Finland) and the Rapid Fetal Fibronectin (fFN)® 10Q Cassette Kit (Hologic, Inc., Marlborough, MA, USA) at thresholds ≠50 ng/ml [quantitative fFN (qfFN)] for women presenting with signs and symptoms of preterm labour relative to fFN at 50 ng/ml. Systematic reviews of the published literature were conducted for diagnostic test accuracy (DTA) studies of PartoSure, Actim Partus and qfFN for predicting preterm birth, the clinical effectiveness following treatment decisions informed by test results and economic evaluations of the tests. A model-based economic evaluation was also conducted to extrapolate long-term outcomes from the results of the diagnostic tests. The model followed the structure of the model that informed the 2015 National Institute for Health and Care Excellence guidelines on preterm labour diagnosis and treatment, but with antenatal steroids use, as opposed to tocolysis, driving health outcomes. Twenty studies were identified evaluating DTA against the reference standard of delivery within 7 days and seven studies were identified evaluating DTA against the reference standard of delivery within 48 hours. Two studies assessed two of the index tests within the same population. One study demonstrated that depending on the threshold used, qfFN was more or less accurate than Actim Partus, whereas the other indicated little difference between PartoSure and Actim Partus. No study assessing qfFN and PartoSure in the same population was identified. The test accuracy results from the other included studies revealed a high level of uncertainty, primarily attributable to substantial methodological, clinical and statistical heterogeneity between studies. No study compared all three tests simultaneously. No clinical effectiveness studies evaluating any of the three biomarker tests were identified. One partial economic evaluation was identified for predicting preterm birth. It assessed the number needed to treat to prevent a respiratory distress syndrome case with a 'treat-all' strategy, relative to testing with qualitative fFN. Because of the lack of data, our de novo model involved the assumption that management of pregnant women fully adhered to the results of the tests. In the base-case analysis for a woman at 30 weeks' gestation, Actim Partus had lower health-care costs and fewer quality-adjusted life-years (QALYs) than qfFN at 50 ng/ml, reducing costs at a rate of £56,030 per QALY lost compared with qfFN at 50 ng/ml. PartoSure is less costly than Actim Partus while being equally effective, but this is based on diagnostic accuracy data from a small study. Treatment with qfFN at 200 ng/ml and 500 ng/ml resulted in lower cost savings per QALY lost relative to fFN at 50 ng/ml than treatment with Actim Partus. In contrast, qfFN at 10 ng/ml increased QALYs, by 0.002, and had a cost per QALY gained of £140,267 relative to fFN at 50 ng/ml. Similar qualitative results were obtained for women presenting at different gestational ages. There is a high degree of uncertainty surrounding the test accuracy and cost-effectiveness results. We are aware of four ongoing UK trials, two of which plan to enrol > 1000 participants. The results of these trials may significantly alter the findings presented here. The study is registered as PROSPERO CRD42017072696. The National Institute for Health Research Health Technology Assessment programme.

Walking to a public transport station

PurposeThe purpose of this paper is to explore the actual walking distance to public transport (PuT) stations and to report passenger perceptions on route choice.Design/methodology/approachA systematic case study has been conducted after administrating a tailor-made paper-based intercept survey in a German city (Munich). It can determine the interrelation between the accessibility of the transit service and evaluation on walking distance acceptance. Statistical analysis and geo-spatial approach were completed for obtaining major findings.FindingsStatistical and geo-spatial analysis shows that respondents living in low-density areas walk longer than residents living in nearby inner city areas. In terms of PuT modes, residents walk longer for suburban train and subway/metro (U-Bahn) than for bus/tram services. Transit users accept a longer walking distance to reach a train station than other PuT modes and they choose the most direct and quickest route to reach PuT stations.Research limitations/implicationsFindings of this study would help to formulate future strategies and standards for the sustainable planning of public transportation systems in the context of Munich and many other cities around the globe with similar conditions. However, future research should be conducted using a large-scale survey for evaluating the comprehensive picture of walking patterns to PuT stations. Accessibility to PuT stations can also be modeled and evaluated by adopting open data and voluntary social media information. Unfortunately, this study only presents a partial evaluation of walking focused on accessibility at selected PuT stations in different settings of the urban fabric.Social implicationsThis empirical study can be considered as an initial finding in the favor of the city transport authority to provide a design scale for improved accessibility of transit users; however, further investigation should be conducted using a large-scale survey for evaluating the comprehensive walking patterns.Originality/valueA systematic case study has been conducted after administrating a tailor-made paper-based intercept survey in a German city (Munich). Findings of this study would help to formulate future strategies and standard for the sustainable planning of the public transportation system in the context of Munich and many other cities in the globe with similar conditions.

Концептуальний підхід до вибору пріоритетних напрямів розвитку спроможностей Збройних Сил України та інших складових сил оборони

Концептуальний підхід до вибору пріоритетних напрямів розвитку спроможностей Збройних Сил України та інших складових сил оборони

Abstract P3-03-23: Which factor of metastatic lymph nodes–The number, tumor volume or anatomical location–Is independently prognostic in breast cancer? - A prospective cohort study using molecular whole-node analysis of all removed axillary nodes

Abstract Background: Axillary lymph node status is one of the most powerful prognostic factors in breast cancer. However, it remains unknown which factor of metastatic lymph nodes–the number, tumor volume or anatomical location–is independently prognostic. Conventional pathological examinations of lymph nodes have limited ability to accurately measure metastatic tumor volume due to the partial evaluation of nodes. On the other hand, the one-step nucleic acid amplification (OSNA) assay, a novel molecular method, can quantify the tumor volume in a whole node based on cytokeratin 19 (CK19) mRNA copy number. In this prospective cohort studyusing the OSNA whole-node analysis, we aimed to elucidate the independent prognostic factor of lymph node metastasis in breast cancer. Patients and Methods: The subjects consisted of 307 cN0 patients with invasive breast cancer, who underwent axillary dissection after a metastatic sentinel node (SN) biopsy and whose SNs and non-SNs were all examined using the OSNA whole-node assaybetween 2009 and 2012.The cut-off values of the OSNA assay for negative/positive results and micro/macrometastasis were defined at 250 and 5,000 copies/μL of CK19 mRNA, respectively. The total tumor volume in the SN or non-SN was defined as the sum of CK19 mRNA copy numbers from all samples in the SN or non-SN. The cut-off value for the total tumor volume in the SN was set at 2,810 copies/μL according to our previous study (Osako et al. Br J Cancer 2017). The anatomical location of metastasis was classified into Level I (confined to SN), Level I (spread to non-SN), or Level II/III. Predictive factors for distant disease-free survival (DDFS) were investigated using the univariate log-rank tests and multivariate Cox proportional hazards models.The median follow-up time was 6.1 years (range, 0.2–8.6). Results: Of the 307 patients, 130 (42.3%) and 177 (57.7%) had the total tumor volume &amp;lt;2,810 and ≥2,810 copies/μL in the SN, respectively. Five-year DDFS was 96.0% in the entire cohort. In the univariate analysis, DDFS was significantly related to the pT classification, grade, hormone receptor status, triple-negative subtype, total tumor volume in the SN and cytotoxic chemotherapy. However, DDFS was not significantly related to the number of metastatic or macrometastatic nodes in the SN, non-SN, or all nodes (i.e. SN + non-SN); the total tumor volume in the non-SN or all nodes; the AJCC pN classification; or the anatomical location of metastasis. In the multivariate analysis, the total tumor volume in the SN (&amp;lt;2810 vs. ≥2810 copies/μL, hazard ratio 5.2, 95% confidence interval 1.2–23.2, P=0.03) and cytotoxic chemotherapy (- vs. +, hazard ratio 0.05, 95% confidence interval 0.02–0.17, P&amp;lt;0.001) remained significant. Conclusions: The total tumor volume in the SN was the independent prognostic factor of lymph node metastasis in SN-positive invasive breast cancer. Accurate evaluation of metastatic tumor burden in the SN can be important for predicting prognosis and may help to guide the precise therapeutic decision making for breast cancer patients. Citation Format: Osako T, Iwase T, Ushijima M, Ogiya A, Ueno T, Ohno S, Akiyama F. Which factor of metastatic lymph nodes–The number, tumor volume or anatomical location–Is independently prognostic in breast cancer? - A prospective cohort study using molecular whole-node analysis of all removed axillary nodes [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-03-23.

TrABin: Trustworthy analyses of binaries

Verification of microkernels, device drivers, and crypto routines requires analyses at the binary level. In order to automate these analyses, in the last years several binary analysis platforms have been introduced. These platforms share a common design: the adoption of hardware-independent intermediate representations, a mechanism to translate architecture dependent code to this representation, and a set of architecture independent analyses that process the intermediate representation. The usage of these platforms to verify software introduces the need for trusting both the correctness of the translation from binary code to intermediate language (called transpilation) and the correctness of the analyses. Achieving a high degree of trust is challenging since the transpilation must handle (i) all the side effects of the instructions, (ii) multiple instruction encodings (e.g. ARM Thumb), and (iii) variable instruction length (e.g. Intel). Similarly, analyses can use complex transformations (e.g. loop unrolling) and simplifications (e.g. partial evaluation) of the artifacts, whose bugs can jeopardize correctness of the results. We overcome these problems by developing a binary analysis platform on top of the interactive theorem prover HOL4. First, we formally model a binary intermediate language and we prove correctness of several supporting tools (i.e. a type checker). Then, we implement two proof-producing transpilers, which respectively translate ARMv8 and CortexM0 programs to the intermediate language and generate a certificate. This certificate is a HOL4 proof demonstrating correctness of the translation. As demonstrating analysis, we implement a proof-producing weakest precondition generator, which can be used to verify that a given loop-free program fragment satisfies a contract. Finally, we use an AES encryption implementation to benchmark our platform.

Higher-order principal component analysis for the approximation of tensors in tree-based low-rank formats

This paper is concerned with the approximation of tensors using tree-based tensor formats, which are tensor networks whose graphs are dimension partition trees. We consider Hilbert tensor spaces of multivariate functions defined on a product set equipped with a probability measure. This includes the case of multidimensional arrays corresponding to finite product sets. We propose and analyse an algorithm for the construction of an approximation using only point evaluations of a multivariate function, or evaluations of some entries of a multidimensional array. The algorithm is a variant of higher-order singular value decomposition which constructs a hierarchy of subspaces associated with the different nodes of the tree and a corresponding hierarchy of interpolation operators. Optimal subspaces are estimated using empirical principal component analysis of interpolations of partial random evaluations of the function. The algorithm is able to provide an approximation in any tree-based format with either a prescribed rank or a prescribed relative error, with a number of evaluations of the order of the storage complexity of the approximation format. Under some assumptions on the estimation of principal components, we prove that the algorithm provides either a quasi-optimal approximation with a given rank, or an approximation satisfying the prescribed relative error, up to constants depending on the tree and the properties of interpolation operators. The analysis takes into account the discretization errors for the approximation of infinite-dimensional tensors. Several numerical examples illustrate the main results and the behavior of the algorithm for the approximation of high-dimensional functions using hierarchical Tucker or tensor train tensor formats, and the approximation of univariate functions using tensorization.

A SQL to C compiler in 500 lines of code

AbstractWe present the design and implementation of a SQL query processor that outperforms existing database systems and is written in just about 500 lines of Scala code – a convincing case study that high-level functional programming can handily beat C for systems-level programming where the last drop of performance matters. The key enabler is a shift in perspective toward generative programming. The core of the query engine is an interpreter for relational-algebra operations, written in Scala. Using the open-source lightweight modular staging framework, we turn this interpreter into a query compiler with very low effort. To do so, we capitalize on an old and widely known result from partial evaluation: the first Futamura projection, which states that a process that can specialize an interpreter to any given input program is equivalent to a compiler. In this context, we discuss lightweight modular staging programming patterns such as mixed-stage data structures (e.g., data records with static schema and dynamic field components) and techniques to generate low-level C code, including specialized data structures and data loading primitives.

Evaluation on Partial Discharge Intensity of Electrical Equipment Based on Improved ANFIS and Ultraviolet Pulse Detection Technology

The ultraviolet pulse detection technology has superiorities in response speed and antijamming capability, so it is extensively applied to insulation detection for electrical equipment. The existing detection and analysis methods have defects, such as failure of precise modeling caused by incomplete analysis of influence factor, poor model adaptability, and complex operation. In allusion to the problems, the ultraviolet pulse detection circuit was optimized and its sensitivity was analyzed through tests. Then, a partial discharge intensity evaluation method for electrical equipment based on the improved adaptive network based fuzzy inference system (improved ANFIS) was proposed combined with the detected pulse count (P), temperature (T) and humidity (H). The initial fuzzy inference system structure was established with the subtractive clustering method (SCM) and fuzzy C-means (FCM) algorithm, and the traditional ANFIS learning algorithm was improved via Fletcher-Reeves conjugate gradient method. In this way, the model parameters were optimized continuously, and the system ability of ignoring small changes in the network was improved. Finally, the effectiveness and practicability of the method were verified through field test. The experimental results demonstrated that the improved ANFIS reduced the model error by 2% when compared with traditional ANFIS, and the model accuracy is improved. Besides, the quantitative precision of the discharge intensity is higher than that of the traditional ANFIS by the contrastive analysis of field test data, indicating that the improved ANFIS evaluate the partial discharge intensity of electrical equipment more accurately. Thus, a decision basis can be provided for the equipment protection and charged maintenance of the electric system.