Search

Informed by the Social-Emotional and Character Development (SECD) approach to school turnaround, the present study examined the relationship between students’ recollection and reflection of their experience in a SECD program and academic achievement and explored the mediating effect of student-teacher relationships. Based on an intervention in an urban New Jersey school district, three data sources were used: program feedback surveys, student self-report surveys that assessed students on key SECD variables, and academic grades. The final sample consisted of 255 youths from two middle schools. Results demonstrated a significant relationship between SECD reflection and academic achievement. Partial mediation also was observed, with an indirect relationship between SECD reflection, student-teacher relationships, and academic achievement. Results of this study imply that positive SECD program reflections and student-teacher relationships can positively, and uniquely, impact academic achievement. Other implications of these findings for future research and practice, as well as the study’s strengths and weaknesses that may have contributed to these results, are discussed.

Chipping potatoes are bred for their ability to produce light-colored, defect-free chips. Chips with stem-end chip defect (SECD) have dark blemishes and are undesirable to consumers and chip processors. The heritability of SECD is not known and genetic loci linked to defect formation have not been identified. Chip processing varieties ‘Wauseon’ and ‘Lenape’ were crossed and tubers from parents and 191 progeny were evaluated over four years for chip color descriptors L*, a*, and b* and SECD score in January, March, and May. Broad sense heritability for SECD was 0.64 or greater at each sampling time. Genotype data were used to construct a 1282 cM linkage map. Nine quantitative trait loci (QTL) for SECD were detected, and seven overlapped QTL for chip color traits. The QTL identified are starting points for developing molecular markers that are used to select genotypes that produce light-colored chips and have resistance to SECD formation.

Considering the key role of social-emotional and character development (SECD) competencies in college, career, and life success — and considering that many of those competencies are teachable — there is no excuse for failing to incorporate them systematically into our education system. That would be the equivalent of depriving children of oxygen. This article is addressed to the U.S. Secretary of Education and other education policymakers and offers them specific recommendations to guide policy that would yield high-quality programs of support for SECD in all schools.

Staphylococcus aureus causes many infections and its drug resistance is a worrying challenge for medical care. The SecD subunit of Sec secretion system in methicillin‐resistant S. aureus is an attractive target because SecD dysfunction leads to the death of bacteria and SecD as a target is more efficient than SecA and SecF. Evolution could have made SecD to become insensitive to antibacterial agents although the drugs directly against SecD have yet to develop. So far, no detailed information on SecD evolution has been available, thus 2686 SecD sequences with full taxonomic information from kingdom to species were analyzed. First, the variance of pairwise p‐distance was evaluated for each taxonomic group. Second, the variance was further partitioned into intergroup and intragroup variances for quantification of horizontal and vertical gene transfer. Third, phylogenetic tree was built to trace the evolutionary pathway. The results showed that overall evolution of SecDs appears to have undergone horizontal and vertical gene transfer. Only 0.5% horizontal transfers were found between any two SecDs in S. aureus, 6.8% and 8.8% horizontal transfers were found between any two Staphylococcus SecDs from different and the same species, and only one SecD from S. aureus was located far away from its sister cluster. Thus, statistic and evolutionary analyses demonstrate that the SecDs from staphylococcus species have a small chance of mutating, and provide taxonomic evidence to use the SecD as a potential target for new generation of antibacterial agents against S. aureus.

(Coinductive) natural semantics is presented as a unifying framework for the verification of total correctness of compilers in Coq (with the feature that a verified compiler can be obtained). In this way, we have a simple, easy, and intuitive framework, to carry out the verification of a compiler, using a proof assistant in which both cases are considered: terminating and non-terminating computations (total correctness).

In this chapter, we make the case and propose policy recommendations to the US Secretary of Education, as well as state commissioners of education and other educational leaders, on how to effectively scale up high-quality social-emotional and character development (SECD) in all schools. First, we define SECD, social-emotional learning (SEL), and related competencies, identify effective approaches to developing these competencies through universal school-based programming, and summarize the known individual, social, and economic benefits of systematic efforts to promote these competencies in schools. Next, we review the current state of US education policy with regard to SEL and SECD, including the scope of program implementation, state standards, preservice and in-service teacher development, evaluation and assessment, and funding. We end the chapter with a set of policy recommendations on how to leverage existing strengths and build further capacity for making SECD an integral and seamless component of the education system.

Cooper and Wadler introduced the RPC calculus, which is obtained by incorporating a mechanism for remote procedure calls (RPC) into the lambda calculus. The location where a caller’s code is executed is designated in a lambda abstraction in the RPC calculus. Nishizaki et al. proposed a simplified abstract machine for the lambda calculus, known as a Simple Abstract Machine (SAM). The configuration of an SECD machine is a quadruple of data sequences: Stack, Environment, Code, and Dump. In contrast, the SAM configuration is a double of data sequences: Stack and Code. In this paper, we introduce a SAM-based abstract machine for the RPC calculus, called a Location-aware Simple Abstract Machine (LSAM). This machine makes it possible to model parallelism more clearly. We provide a translation of the RPC calculus into LSAM, and prove a correctness theorem for the translation. We then show that the translation can be extended to allow parallel execution in LSAM.

Bacteria, Archaea and Eukaryotes have evolved a plethora of mechanisms to translocate proteins across their various membranes. The bacterial Sec pathway is ubiquitous and essential for cell viability and is used by most proteins destined for the inner membrane, the periplasm or beyond. In bacteria, Sec system components include the heterotrimers SecY/SecE/SecG and SecD/SecF/YajC and the peripherally associated ATPase motor SecA. SecA in solution is mainly dimeric. Unexpectedly, structures of SecA dimers from different or even the same bacterium do not have a consistent dimerization interface. Analysis of the functional assembled translocase complexes blurs the picture even further as the functional quaternary state of the SecYEG channel is also disputed. Several experimental approaches tried to define the oligomeric state of SecA during preprotein 'pushing' through SecYEG. One high-resolution SecA-SecYEG complex has been visualized. This snapshot might be a step closer to the actual translocating machinery. Nevertheless, because of the use of detergent, the true quartenary state of the translocase might have been disturbed. Hence, even after this and other studies, several issues remain puzzling. New approaches must be combined with current tools to gain insight into the functionally relevant quartenary states of SecA and SecYEG during preprotein translocation.

The Peter Landin prize honours the best paper presented at each year's International Symposium on the Implementation and Application of Functional Languages (IFL). It has been awarded every year since 2003, and covers a range of topics including functional operating systems, static analysis for cost information of functional programs, techniques to improve array processing for data locality and parallelism, explicit parallel coordination, supercompilation, and a rational deconstruction of Landin's SECD machine itself. This article describes the history of the prize, explains why Peter Landin was chosen as nominee, and describes each of the articles that have been awarded the prize to date.

There is a missing piece to America’s education agenda, and children will continue to be left behind until that piece is addressed. Furthermore, children are not being systematically prepared for their complex roles as citizens in our democracy. A growing body of evidence from research and practice suggests reconceptualizing education as an integration of social-emotional and character development (SECD) and academic learning. This article reviews skills children need for effective social and academic participation, characteristics of schools that effectively integrate these forms of learning, and key reasons to adopt this integration. It concludes with examples of, and suggestions for, bringing SECD to prominence in educational policy making.

We define logical relations between the denotational semantics of a simply typed functional language with recursion and the operational behaviour of low-level programs in a variant SECD machine. The relations, which are defined using biorthogonality and stepindexing, capture what it means for a piece of low-level code to implement a mathematical, domain-theoretic function and are used to prove correctness of a simple compiler. The results have been formalized in the Coq proof assistant.

The process of compiler generation from lambda-calculus definitions is studied. The compiling schemes developed utilize as their object language the set of state transition machines (STMs): automata-like transition sets using first-order arguments. An intermediate definition form, the STM-interpreter, is treated as central to the formulation of STMs. Three compiling schemes are presented: one derived directly from an STM-interpreter for the lambda-calculus; one formulated from an STM-interpreter variant of Landin's SECD-machine; and one defined through meaning-preserving transformations upon a denotational definition of the lambda-calculus. The results are compared and some tentative conclusions are made regarding the utility of compiler generation with the STM forms.

Chargueraud [6] lists three ways of verifying functional programs: first is to define Hoare triples, second is to define programs directly in a theorem prover, that is shallow embedding and the third is to define the semantics of the language in the logic of a theorem prover, use this definition to write programs and then prove correctness of these, this is called deep embedding.

New software tools for quantitative analysis of mass spectrometric lipidome data have been developed. The LIMSA tool finds and integrates peaks in a mass spectrum, matches the peaks with a user-supplied list of expected lipids, corrects for overlap in their isotopic patterns, and quantifies the identified lipid species according to internal standards. Three different algorithms for isotopic correction (deconvolution) were implemented and compared. LIMSA has a convenient user interface and can be applied on any type of MS spectrum. Typically, analysis of one spectrum takes only a few seconds. The SECD tool, designed for analysis of LC-MS data sets, provides an intuitive and informative display of MS chromatograms as two-dimensional "maps" for visual inspection of the data and allows the user to extract mass spectra, to be further analyzed with LIMSA, from arbitrary regions of these maps. More reliable analysis of complex lipidome data with improved signal-to-noise ratio is obtained when compared to standard time-range averaged spectra. The functionality of these tools is demonstrated by analysis of standard mixtures as well as complex biological samples. The tools described here make accurate, high-throughput analysis of extensive sample sets feasible and are made available to the scientific community free of charge.

The majority of secretory proteins are translocated into and across hydrophobic membranes via the universally conserved Sec pore. Accessory proteins, including the SecDF-YajC Escherichia coli membrane complex, are required for efficient protein secretion. E. coli SecDF-YajC has been proposed to be involved in the membrane cycling of SecA, the cytoplasmic bacterial translocation ATPase, and in the stabilizing of SecG, a subunit of the Sec pore. While there are no identified archaeal homologs of either SecA or SecG, many archaea possess homologs of SecD and SecF. Here, we present the first study that addresses the function of archaeal SecD and SecF homologs. We show that the SecD and SecF components in the model archaeon Haloferax volcanii form a cytoplasmic membrane complex in the native host. Furthermore, as in E. coli , an H. volcanii Δ secFD mutant strain exhibits both severe cold sensitivity and a Sec-specific protein translocation defect. Taken together, these results demonstrate significant functional conservation among the prokaryotic SecD and SecF homologs despite the distinct composition of their translocation machineries.

The activation of human epidermal growth factor receptor (hEGFR) involves a large conformational change in its soluble extracellular domains (sECD, residues 1-620), from a tethered to an extended conformation upon binding of ligands, such as EGF. It has been reported that this dynamic process is pH-dependent, that is, hEGFR can be activated by EGF at high pH to form an extended dimer but remains as an inactive monomer at low pH. In this paper, we perform all-atom molecular dynamics (MD) simulations starting from the tethered conformation of sECD:EGF complex, at pH 5.0 and 8.5, respectively. Simulation results indicate that sECD:EGF shows different dynamic properties between the two pHs, and the complex may have a higher tendency of activation at pH 8.5. Twenty residues, including 13 histidines, in sECD:EGF have different protonation states between the two pHs (calculated by the H++ server). The charge distribution at pH 8.5 is more favorable for forming an extended conformation toward the active state of sECD than that at pH 5.0. Our study may shed light on the mechanism of pH dependence of hEGFR activation. Graphical abstract pH dependence of ligand-induced human epidermal growth factor receptor activation.

A remarkable feature of proteins of the SecD and SecF family involved in protein translocation is that they possess a very large first periplasmic domain. Here we report that this large first periplasmic domain is not required for the SecD-SecF interaction but that it is important for catalyzing protein translocation.

We analyse machines that implement the call-by-value reduction strategy of the λ-calculus: two environment machines – CAM and SECD – and two encodings into the $\pi$-calculus – due to Milner and Vasconcelos. To establish the relation between the various machines, we setup a notion of reduction machine and two notions of correspondences: operational – in which a reduction step in the source machine is mimicked by a sequence of steps in the target machine – and convergent – where only reduction to normal form is simulated. We show that there are operational correspondences from the λ-calculus into CAM, and from CAM and from SECD into the $\pi$-calculus. Plotkin completes the picture by showing that there is a convergent correspondence from the λ-calculus into SECD.

The Escherichia coli preprotein translocase is composed of a "preprotein conducting channel" domain that consists of the peripherally bound translocation ATPase SecA and the heterotrimeric SecYEG membrane protein complex. SecD, SecF, and YajC form another heterotrimeric complex that can associate with the SecYEG complex. YidC is an essential membrane protein that plays a role in the integration of newly synthesized membrane proteins, and has been shown to co-purify with SecYEG when all translocase components are overproduced. Here, we demonstrate that under conditions that YidC co-purifies with overproduced SecDFyajC it does not co-purify with overproduced SecYEG. Moreover, this interaction of YidC with the SecDFyajC complex is also found at chromosomal protein levels of SecD, SecF and YajC. Closer examination of the SecDFyajC-YidC complex showed that YidC binds to SecD and SecF, whereas YajC interacts only with SecF. As SecF and YajC have previously been shown to interact with SecY, we propose that these two proteins link the heterotetrameric SecDFyajC-YidC complex to the SecYEG complex.

Vibrio alginolyticus caused great losses to aquaculture. Adhesion is an important virulence factor of V. alginolyticus. In this study, the relationship between V. alginolyticus adhesion and type II secretion system genes (secA, secD, secF, yajC, and yidC) was determined using gene silencing, qRT‐PCR and in vitro adhesion assay. The results showed that the expression of target genes and the bacterial adhesion exhibited significant decreases after transient gene silencing and stable gene silencing, which indicated that secA, secD, secF, yajC, and yidC played roles in the bacterial adhesion of V. alginolyticus. The expression of secA, secD, secF, yajC, and yidC were significantly influenced by temperature, salinity, pH and starvation. The results indicated that the expression of secA, secD, secF, yajC, and yidC were sensitive to different environmental factors, whereas environmental factors can affect V. alginolyticus adhesion via the expression of secA, secD, secF, yajC, and yidC.

We present a new abstract machine, called DCESH, which models the execution of higher-order programs running in distributed architectures. DCESH implements a native general remote higher-order function call across node boundaries. It is a modernised version of SECD enriched with specialised communication features required for implementing the remote procedure call mechanism. The key correctness result is that the termination behaviour of the remote procedure call is indistinguishable (bisimilar) to that of a local call. The correctness proofs and the requisite definitions for DCESH and other related abstract machines are formalised using Agda. We also formalise a generic transactional mechanism for transparently handling failure in DCESHs.We use the DCESH as a target architecture for compiling a conventional call-by-value functional language ("Floskel") which can be annotated with node information. Conventional benchmarks show that the single-node performance of Floskel is comparable to that of OCaml, a semantically similar language, and that distribution overheads are not excessive.

It is well-known that many environment-based abstract machines can be seen as strategies in lambda calculi with explicit substitutions (ES). Recently, graphical syntaxes and linear logic led to the linear substitution calculus (LSC), a new approach to ES that is halfway between small-step calculi and traditional calculi with ES. This paper studies the relationship between the LSC and environment-based abstract machines. While traditional calculi with ES simulate abstract machines, the LSC rather distills them: some transitions are simulated while others vanish, as they map to a notion of structural congruence. The distillation process unveils that abstract machines in fact implement weak linear head reduction, a notion of evaluation having a central role in the theory of linear logic. We show that such a pattern applies uniformly in call-by-name, call-by-value, and call-by-need, catching many machines in the literature. We start by distilling the KAM, the CEK, and a sketch of the ZINC, and then provide simplified versions of the SECD, the lazy KAM, and Sestoft's machine. Along the way we also introduce some new machines with global environments. Moreover, we show that distillation preserves the time complexity of the executions, i.e. The LSC is a complexity-preserving abstraction of abstract machines. Fil: Accattoli, Beniamino. Universidad de Bologna; Italia. University of Carnegie Mellon; Estados Unidos Fil: Barenbaum, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires; Argentina Fil: Mazza, Damiano. Centre National de la Recherche Scientifique; Francia. Universite de Paris 13-Nord; Francia

One method for producing verified implementations of programming languages is to formally derive them from abstract machines. Tail-recursive abstract machines provide efficient support for iterative processes via the ordinary procedure call mechanism. This document argues that the use of tail-recursive abstract machines incurs only a small increase in theorem-proving burden when compared with what is required when using ordinary abstract machines. The position is supported by comparing correctness proofs performed using the Boyer–Moore theorem prover. A by-product of this effort is a syntactic criterion based on tail contexts for identifying which procedure calls must be implemented as tail calls. The concept of tail contexts was used in the latest Scheme Report, the only language specification known to the author that defines the requirement that its implementations must be tail recursive.

This note introduces Peter Landin‘s 1965 technical report “A Generalization of Jumps and Labels”, which is reprinted in this volume. Its aim is to make that historic paper more accessible to the reader and to help reading it in context. To this end, we explain Landin‘s control operator J in more contemporary terms, and we recall Burge‘s solution to a technical problem in Landin‘s original account.

The effect of the overproduction of SecF encoded by the tac-secF gene on a plasmid on the synthesis of other Sec proteins was studied in Escherichia coli. SecF overproduction resulted in the simultaneous overproduction of SecD encoded by the tac-secD gene on a plasmid. Deletion of the orf6 gene, located downstream of the secF gene, had no effect on SecD overproduction. A pulse-chase experiment revealed that the overproduction was due to stabilization of SecD with SecF. SecF overproduction also resulted in the overproduction of SecY encoded by the tac-secY gene on a plasmid as well. SecF overproduction also enhanced the level of SecY expressed by the chromosomal secY gene. This SecF effect was not due to its effect on SecD or SecE, since SecF overproduction did not affect the levels of SecD and SecE expressed by the chromosomal secD and secE genes, respectively. SecE-dependent overproduction of SecY has already been demonstrated. It is suggested that SecF interacts with both SecD and SecY. SecE-SecY interaction has been demonstrated. It is likely, therefore, that all Sec proteins in the cytoplasmic membrane interact with each other.

Mutations in secD and secF show impaired protein translocation across the inner membrane of Escherichia coli. We investigated the effect of SecD and SecF (SecD/F) depletion on preprotein translocation into inverted inner membrane vesicles (IMVs). Both IMVs and cells which were depleted of SecD/F were defective in their ability to maintain a proton electrochemical gradient. The translocation of pre-maltose binding protein (preMBP), which is strongly delta microH+ dependent, showed a 5-fold decreased rate with IMVs lacking SecD/F. In contrast, proteolytic processing of preMBP to MBP by leader peptidase was similar in IMVs containing and lacking SecD/F, consistent with earlier findings that only ATP-dependent translocation is required for the initiation of translocation. In the absence of a delta microH+, with ATP as the sole energy source, preMBP translocation into IMVs which contained or were depleted of SecD/F was identical. Translocation of the precursor of outer membrane protein A (proOmpA) in the presence of subsaturating ATP also required a generated delta microH+ and, under these conditions, proOmpA translocation required SecD/F. With saturating concentrations of ATP, where delta microH+ has little effect on in vitro proOmpA translocation, SecD/F also had little effect on translocation. These results explain why SecD/F effects are precursor protein dependent in vitro.

The secD operon of Escherichia coli is required for the efficient export of proteins. We have characterized this operon, and found that, in addition to secD and secF, it contains the upstream gene yajC, but not the genes queA or tgt, in contrast to previous reports. An analysis of yajC mutations constructed in vitro and recombined onto the chromosome indicates that yajC is neither essential nor a sec gene. The secD operon is not induced in response to either secretion defects or temperature changes. TnphoA fusions have been used to analyze the topology of SecD in the inner membrane; the protein contains six transmembrane stretches and a large periplasmic domain. TnphoA fusions to SecD and SecF have also been recombined onto the chromosome and used to determine the level of these proteins within the cell. Our results indicate that there are fewer than 30 SecD and SecF molecules per cell.

Modern type systems for programming languages usually incorporate additional information useful for program analysis, e.g., effects, control flow, non-interference, strictness etc. When designing a typing predicate for such systems, a form of logical derivation rules is normally taken. Despite the expressivity of this approach, the straightforward implementation of an appropriate type checker is usually inefficient in terms of stack consumption and further optimisations. This leads to a significant gap between an analysis and program implementing the analysis. In this paper we demonstrate an application of techniques investigated by Danvy et al. to derive an abstract machine for typing from the traditional recursive descent approach. All used techniques are off-the-shelf and no appropriate correspondence theorems between an initial type system and the derived abstract machine needs to be proven: they are instead corollaries of the correctness of inter-derivation and of the initial specification. Whereas a recursive descent is something straightforward to implement based on declarative typing rules, the derived abstract machine exposes behaviour similar to Landin's SECD machine and gives a solid basis for further optimizations using abstract interpretation. ispartof: pages:1-7 ispartof: LDTA '11 Proceedings of the Eleventh Workshop on Language Descriptions, Tools and Applications pages:1-7 ispartof: LDTA location:Saarbrucken, Germany date:26 Mar - 27 Mar 2011 status: published

Many kinds of abstract machine have been proposed for executing byte codes of functional languages, such as Landin's SECD machine and Curien's Categorical Abstract Machine, which have been studied for decades from a theoretical viewpoint and applied in the implementation of functional language processors. In this paper, we propose the Simple Abstract Machine (SAM), a simplified SECD machine. The simplification lets us handle first-class continuations in the framework of abstract machines.

In this chapter, we present the main properties of functional programming. In functional programming, computation proceeds by rewriting functions and not by modifying the state. The fundamental characteristic of the languages in this paradigm, at least in their “pure” form, is precisely that of not possessing the concept of memory (and therefore side effect). Once an environment is fixed, an expression always denotes the same value. We will discuss the pure paradigm in the first sections, explaining the fundamental aspects. Functional programming languages, however, merge these “pure” ingredients in a context that adds many other mechanisms; we will review them before touching upon the SECD machine, an abstract machine for higher-order functional languages which constitutes the prototype of many real implementations. We will, at this point, be in a position to discuss the reasons why the functional programming paradigm is interesting with respect to ordinary imperative languages. The chapter concludes with a more theoretical section which provides a succinct introduction to the lambda-calculus, a formal system for computability which inspires all functional languages and which has been a constant model for the design of programming languages.

An abstract machine is designed to support the data environment requirements of BaLinda Lisp, a parallel Lisp dialect which permits speculative processing of conditional modules. Logically, the machine provides multiple stacks connected into an environment tree, with lexically visible sections pointed to by display registers. Physically, stack sections are stored as separate objects and access is established by the use of a dynamic stack recording the chain of function calls, and a set of lexical display registers pointing at visible objects. This arrangement allows parts of the environment of a function to be retained or garbage-collected as appropriate after exit. By making copies of visible ancestral stack sections, side effects of speculative parallel tasks are handled in accordance with language semantics. The architecture is generic and may be realized in a variety of forms, depending on whether BaLinda Lisp is implemented on a conventional machine, stack machine, or dataflow machine.

SecD and SecF proteins were overproduced by means of recombinant DNA technology. Immunoblot and amino-acid sequencing analysis revealed that the overproduced proteins are SecD and SecF. The SecD- or SecF-overproduced membrane fraction was subjected to differential solubilization. The SecD protein was then purified through ion-exchange and size-exclusion chromatographies. The SecF protein was purified through size exclusion chromatography. Proteoliposomes reconstituted from the purified SecD and SecF together with SecE and SecY were used to analyze the translocation activity. SecD and SecF did not exhibit significant effects on the translocation activity of proteoliposomes. The amounts of SecD and SecF in overproducers were determined densitometrically on a stained SDS gel and their overproduction (fold) was determined by means of immunoblot analysis. Then the number of these molecules in one normal cell were estimated. From these numbers, together with those of other Sec proteins, the number of the translocation machinery existing in one Escherichia coli cell was inferred to be around 500.

This technical paper provides an overview of Rome Laboratory's Research & Development Program in the area of System Engineering. In particular, it describes the objectives of an exploratory development effort entitled “System Engineering Concept Demonstration” (SECD), the activities that were pursued under the effort, and its results. It serves as an introduction to other papers [Comer 1992], [Ortiz 1992], and [Pariseau & Stuebing 1992], which provide further detail on the technology and demonstrations that resulted. Rome Laboratory's future plans to develop Systems Engineering technology are also identified.

This technical paper will present a summary of the SECD Process Model Task sponsored by Rome Laboratory at Griffiss Air Force Base, New York. An introduction to the SECD Program is presented in the “SECD - Overview” [LaMonica 1992]. The SECD Process Model is a system acquisition and development model with emphasis on system engineering activities over the entire system life cycle. The Process Model is a graphical and textual representation of the system engineering life cycle activities, agents, flows, feedbacks, and work products. This interactive Process Model provides a multidimensional view of government acquisition and contractor development activities. In the context of the SECD Program, the Process Model validates the System /Segment Specification (SSS) requirements and demonstrates coverage and completeness of the system engineering process.

A concurrent functional language is presented, Parlam, which includes primitives for explicit control of parallel reductions. An abstract machine for Parlam (ParSEC) is derived from Landin's SECD machine by extending it for dealing with parallel computation. Several issues and problems about its implementation on a massively parallel computer are discussed and a specific implementative model for ParSEC under the Connection Machine is described.

We define logical relations between the denotational semantics of a simply typed functional language with recursion and the operational behaviour of low-level programs in a variant SECD machine. The relations, which are defined using biorthogonality and stepindexing, capture what it means for a piece of low-level code to implement a mathematical, domain-theoretic function and are used to prove correctness of a simple compiler. The results have been formalized in the Coq proof assistant.

This paper describes a new implementation technique calledpreliminary arrangements of arguments for lazy functional languages. Unlike conventional lazy evaluators, the evaluator with preliminary arrangements partly processes every argument before calling functions. It works in a lazy way with less memory cells than conventional methods. The practical importance of this technique is demonstrated by some benchmark results.

We present a nondeterministic calculus of closures for the evaluation of λ-calculus, which is based, not on symbolic evaluation (β-reduction), but on the paradigm of environments and closures, as in the old SECD machine, or in the more recent Categorical Abstract Machine (CAM). This calculus stands as a suitable abstraction right above those devices: there is no commitment as to the order of evaluation, and no explicit handling of stacks: the calculus is expressed in the style of Structural Operational Semantics, by a set of conditional rewrite rules. The CAM, and a very simple lazy abstract machine, due to J.-L. Krivine, arise naturally by first restricting the calculus to a specific strategy, and then implementing recursive calls by a stack. The Church–Rosser property and termination in presence of types hold in the calculus of closures, and are easier to establish than in the λ-calculus. The calculus of closures has served as a starting point to a more powerful general calculus of substitutions at which we hint shortly, insisting on its category- theoretic significance.

XQuery is a XML query language proposed by W3C and a good many researches are involved for the implementation of XQuery. While many implementations adopt interpret solutions, XQC is a compiler for XQuery 1.0 which can compile XQuery program to the low level binary code - Java bytecode, and provides opportunities for performance improving. XQC has a well-designed architecture which makes various optimization strategies can be introduced into different compilation phases, and consequently, the compiled bytecode turns out to be efficient during execution, especially during repetitive execution. This paper presents XQC solution through an overview of the architecture which is composed of 4 core modules: preprocessor, FXQL code generator, SECD code generator, and bytecode generator, also it covers the tradeoffs in the core modules in detail and the performance of XQC by experiment.

Landin's J operator was the first control operator for functional languages. It was specified with an extension of the SECD machine, which was the first abstract machine for functional languages. We present a family of compositional evaluation functions corresponding to this extension of the SECD machine, using a series of elementary transformations (transformation into continuation-passing style (CPS) and defunctionalization, chiefly) and their left inverses (transformation into direct style and refunctionalization). To this end, we modernize the SECD machine into a bisimilar one that operates in lock step with the original one but that (1) does not use a data stack and (2) uses the caller-save rather than the callee-save convention for environments. We then characterize the J operator in terms of CPS and in terms of delimited-control operators in the CPS hierarchy. As a byproduct, we also present a reduction semantics for applicative expressions with the J operator, based on Curien's original calculus of explicit substitutions. This reduction semantics mechanically corresponds to the modernized version of the SECD machine and to the best of our knowledge, it provides the first syntactic theory of applicative expressions with the J operator. The present work is concluded by a motivated wish to see Landin's name added to the list of co-discoverers of continuations. Methodologically, however, it mainly illustrates the value of Reynolds's defunctionalization and of refunctionalization as well as the expressive power of the CPS hierarchy (a) to account for the first control operator and the first abstract machine for functional languages and (b) to connect them to their successors.

We describe the architecture of a virtual machine for executing functional logic programming languages. A distinguishing feature of our machine is that it preserves the operational completeness of non-deterministic programs by concurrently executing a pool of independent computations. Each computation executes only root-needed sequential narrowing steps. We describe the machine's architecture and instruction set, and show how to compile overlapping inductively sequential programs to sequences of machine instructions. The machine has been implemented in Java and in Standard ML.