Use Of Checkpoints Research Articles

Positional Accuracy Assessment of Digital Elevation Models and 3D Vector Datasets Using Check-Surfaces

This study focuses on the positional accuracy of Digital Elevation Models (DEMs) and 3D vector features by considering that both datasets can be used as a product to assess or as a reference. The main objective is to provide an alternative method to the traditional use of checkpoints by using check-surfaces in order to avoid identification issues. The methodology includes the determination of a set of polygons with a significant height in relation to the surrounding area (elevated or depressed) and those cells extracted from the DEM that match these elements. The check-surfaces are obtained after a triangulation of these polygons. The methodology uses procedures based on buffers to provide several results in the form of distribution functions of accuracies (2D, vertical and 3D). The trial has been carried out using a large set of data representing buildings obtained from official institutions. The results show consistent 2D, vertical and 3D accuracy values related to commonly used confidence levels. The application has demonstrated the viability of this approach for obtaining horizontal and vertical accuracies individually and jointly at any confidence level. In addition, the study includes the analysis of the results of specific zones, considering several characteristics.

A Method of Intraoperative Registration Verification to Prevent Accuracy Errors in Robot-Assisted Stereotactic Electroencephalography Electrode Placement

Robotic-assisted stereotactic electroencephalography (sEEG) electrode placement is increasingly common at specialized epilepsy centers. High accuracy and low complication rates are essential to realizing the benefits of sEEG surgery. The aim of this study was to describe for the first time in the literature a method for a stereotactic registration checkpoint to verify intraoperative accuracy during robotic-assisted sEEG and to report our institutional experience with this technique. All cases performed with this technique since the adoption of robotic-assisted sEEG at our institution were retrospectively reviewed. In 4 of 111 consecutive sEEG operations, use of the checkpoint detected an intraoperative registration error, which was addressed before completion of sEEG electrode placement. The use of a registration checkpoint in robotic-assisted sEEG surgery is a simple technique that can prevent electrode misplacement and improve the safety profile of this procedure.

Sequential changepoint detection in neural networks with checkpoints

We introduce a framework for online changepoint detection and simultaneous model learning which is applicable to highly parametrized models, such as deep neural networks. It is based on detecting changepoints across time by sequentially performing generalized likelihood ratio tests that require only evaluations of simple prediction score functions. This procedure makes use of checkpoints, consisting of early versions of the actual model parameters, that allow to detect distributional changes by performing predictions on future data. We define an algorithm that bounds the Type I error in the sequential testing procedure. We demonstrate the efficiency of our method in challenging continual learning applications with unknown task changepoints, and show improved performance compared to online Bayesian changepoint detection.

Analysis of quality control efficiency in the automotive industry

The paper deals with the issue relating to the improvement of the production process through the use of checkpoints. Quality control points used in an industrial enterprise manufacturing oil pans for heavy vehicles are discussed. The study aimed to present a proposal for a method for analyzing the effectiveness of individual control methods used as part of quality control in the manufacturing process of a product and to analyze the relationship between the type of quality control methods and their contribution to the detection of nonconformities of the product - an oil pan. By locating the control point with the highest share of product nonconformity detection, it is possible to take improvement actions - reducing control points by less effective ones. This action will contribute to cost reduction and shortening of the production process time. Due to the increasing demands on the efficiency and effectiveness of control points of automotive powertrain components, this issue is important and topical.

Providing a new approach to increase fault tolerance in cloud computing using fuzzy logic

ABSTRACT It is generally accepted that with the ever-increasing need of users to various resources, cloud computing is rapidly evolving as one of the new practical technologies. Cloud computing can be categorized as a computing solution in which required technology or services allow users to access computing resources on demand. Moreover, fault tolerance is one of the major concerns to ensure availability and reliability of services as well as to perform the tasks. In order to minimize the impact of failures on the system and ensure correct task execution, they must be anticipated and managed. Few newly developed methods for fault tolerance have focused on fault detection dimension. Therefore, in this paper, a detailed analysis of the nature of the error and its detection will provide as well as a fuzzy-based method to prepare an appropriate response to the error tolerance. In order to increase the error tolerance and load balancing when the error occurs, the requesting a task re-execution and migration techniques through the checkpoint are used. The migration technique overlaps with time, so check-point use can avoid re-execution as well as tasks as much as possible. The results of the experiments also indicate a mean superiority of 6.49% for accuracy criterion in comparison with ABFT method and 2.27% in comparison with FFD algorithm.

Rapid and sustained response to immune checkpoint inhibition in cutaneous squamous cell carcinoma after allogenic hematopoietic cell transplant for s\xe9zary syndrome

BackgroundCutaneous squamous cell carcinoma (cSCC) is not uncommon in association with indolent malignancies that were treated with prior radiotherapy and after allogenic bone marrow transplantation. On the other hand, cutaneous T-cell lymphoma (CTCL) is a subtype of non-Hodgkin’s lymphoma which is characterized by an indolent course, with relative refractoriness to conventional chemotherapies and radiotherapy, and occasionally referred for allogeneic hematopoietic cell transplantation (allo-HCT). Recently, the use of immune checkpoint inhibitors has gained attention in the treatment of both cutaneous squamous cell carcinoma and hematological malignancies. However, many patients with hematological malignancies eventually undergo allo-HCT, raising the concern of potential adverse events (graft versus host disease) due to manipulation of the immune system with use of checkpoint inhibitors.Case presentationWe describe a patient with relapsed refractory CTCL (Sézary Syndrome) who underwent allo-HCT with persistence of disease post-transplant. The patient additionally developed a progressively worsening lesion on the right shoulder which was biopsied and showed poorly differentiated carcinoma (cSCC). Pembrolizumab was started for the treatment of cSCC. After second cycle of treatment, the cSCC lesion responded dramatically to the use of immune checkpoint inhibitor. Also, the patient experienced significant resolution of pruritus and generalized erythema. During 24 months of follow up after initial treatment with checkpoint inhibition immunotherapy, the patient showed durable response of both cSCC and CTCL, as well as restoration of full donor chimerism, without obvious worsening of graft versus host disease (GVHD).ConclusionThis is the first case to our knowledge of rapid and durable response of both cSCC and CTCL to immune checkpoint inhibition after allo-HCT. Although this report highlights the potential for significant response to this class of medication, further studies are required to confirm the efficacy and safety of this approach in patients with CTCL after allo-HCT given the potential concern of GVHD.

Merkel Cell Carcinoma, Version 1.2018, NCCN Clinical Practice Guidelines in Oncology.

This selection from the NCCN Guidelines for Merkel Cell Carcinoma (MCC) focuses on areas impacted by recently emerging data, including sections describing MCC risk factors, diagnosis, workup, follow-up, and management of advanced disease with radiation and systemic therapy. Included in these sections are discussion of the new recommendations for use of Merkel cell polyomavirus as a biomarker and new recommendations for use of checkpoint immunotherapies to treat metastatic or unresectable disease. The next update of the complete version of the NCCN Guidelines for MCC will include more detailed information about elements of pathology and addresses additional aspects of management of MCC, including surgical management of the primary tumor and draining nodal basin, radiation therapy as primary treatment, and management of recurrence.

The Praetorians: An Analysis of U.S. Border Patrol Checkpoints Following Martinez-Fuerte

This Note analyzes interior immigration checkpoints following the US Supreme Court’s decision in United States v. Martinez-Fuerte, which upheld the use of checkpoints for the narrow purpose of conducting brief, routine questioning of persons traveling within the United States in order to verify a person’s citizenship and immigration status. The Court’s holding, however, has been broadened by Border Patrol officials to cover other law enforcement functions such as apprehending narcotics and weapons. This broader use of the checkpoints “subverts the rationale of Martinez-Fuerte and turns a legitimate administrative search into a massive violation of the [Constitution].” This Note makes several proposals that could curtail the abusive practices that have taken place at the checkpoints since the Court’s decision in Martinez-Fuerte. First, it recommends that Congress install an ombudsman with the purpose of overseeing border patrol operations at the checkpoints. The ombudsman would be primarily concerned with remedying the current lack of data surrounding activity at the checkpoint and documenting such activity in order for the information to be used to assess the checkpoints from a cost-benefit standpoint. Second, and somewhat an additional function of the ombudsman, this Note recommends that Congress and/or the Department of Homeland Security implement a readily-accessible complaint forum for individuals who suffer constitutional grievances at the checkpoints. Third, this Note recommends that border patrol adopt a monitoring system for regular travelers; namely, a mirror-like SENTRI system that requires extensive background checks and readily apparent ways for border patrol to identify trustworthy individuals at the checkpoints. Finally, this Note recommends that even if Congress or the agencies mentioned in the discussion fail to implement reformative measures to curtail abuse at the checkpoints, the United States Supreme Court should intervene in a future case involving the application of fundamental constitutional rights at the checkpoints in order to clarify whether it intended the checkpoints to effectively operate as crime checkpoints rather than immigration checkpoints. The former has resulted in millions of individuals forgoing the exercise of their constitutional rights within the United States at the mercy of the powerful arm of the government.

Message Efficient Checkpointing and Rollback Recovery in Heterogeneous Mobile Networks

Heterogeneous networks provide an appealing way of expanding the computing capability of mobile networks by combining infrastructure-less mobile ad-hoc networks with the infrastructure-based cellular mobile networks. The nodes in such a network range from low-power nodes to macro base stations and thus, vary greatly in their capabilities such as computation power and battery power. The nodes are susceptible to different types of transient and permanent failures and therefore, the algorithms designed for such networks need to be fault-tolerant. The article presents a checkpointing algorithm for the rollback recovery of mobile hosts in a heterogeneous mobile network. Checkpointing is a well established approach to provide fault tolerance in static and cellular mobile distributed systems. However, the use of checkpointing for fault tolerance in a heterogeneous environment remains to be explored. The proposed protocol is based on the results of zigzag paths and zigzag cycles by Netzer–Xu. Considering the heterogeneity prevalent in the network, an uncoordinated checkpointing technique is employed. Yet, useless checkpoints are avoided without causing a high message overhead.

Effects of enforcement intensity on alcohol impaired driving crashes

BackgroundResearch measuring levels of enforcement has investigated whether increases in police activities (e.g., checkpoints, driving-while-intoxicated [DWI] special patrols) above some baseline level are associated with reduced crashes and fatalities. Little research, however, has attempted to quantitatively measure enforcement efforts and relate different enforcement levels to specific levels of the prevalence of alcohol-impaired driving. ObjectiveThe objective of this study was to investigate the effects of law-enforcement intensity in a sample of communities on the rate of crashes involving a drinking driver. We analyzed the influence of different enforcement strategies and measures: (1) specific deterrence – annual number of driving-under-the-influence (DUI) arrests per capita; (2) general deterrence – frequency of sobriety checkpoint operations; (3) highly visible traffic enforcement – annual number of traffic stops per capita; (4) enforcement presence – number of sworn officers per capita; and (5) overall traffic enforcement – the number of other traffic enforcement citations per capita (i.e., seat belt citations, speeding tickets, and other moving violations and warnings) in each community. MethodsWe took advantage of nationwide data on the local prevalence of impaired driving from the 2007 National Roadside Survey (NRS), measures of DUI enforcement activity provided by the police departments that participated in the 2007 NRS, and crashes from the General Estimates System (GES) in the same locations as the 2007 NRS. We analyzed the relationship between the intensity of enforcement and the prevalence of impaired driving crashes in 22–26 communities with complete data. Log-linear regressions were used throughout the study. ResultsA higher number of DUI arrests per 10,000 driving-aged population was associated with a lower ratio of drinking-driver crashes to non-drinking-driver crashes (p=0.035) when controlling for the percentage of legally intoxicated drivers on the roads surveyed in the community from the 2007 NRS. Results indicate that a 10% increase in the DUI arrest rate is associated with a 1% reduction in the drinking driver crash rate. Similar results were obtained for an increase in the number of sworn officers per 10,000 driving-age population. DiscussionWhile a higher DUI arrest rate was associated with a lower drinking-driver crash rate, sobriety checkpoints did not have a significant relationship to drinking-driver crashes. This appeared to be due to the fact that only 3% of the on-the-road drivers were exposed to frequent sobriety checkpoints (only 1 of 36 police agencies where we received enforcement data conducted checkpoints weekly). This low-use strategy is symptomatic of the general decline in checkpoint use in the U.S. since the 1980s and 1990s when the greatest declines in alcohol-impaired-driving fatal crashes occurred. The overall findings in this study may help law enforcement agencies around the country adjust their traffic enforcement intensity in order to reduce impaired driving in their community.

Immigration Policy and Access to Health Services

Section 287(g) of the Immigration and Nationality Act (INA), added in 1996, authorizes the U.S. Immigration and Custom Enforcement (ICE) to enter into agreements with state and local law enforcement agencies to enforce federal immigration law during their regular, daily law-enforcement activity (www.ice.gov/287g). The original intent was to “target and remove undocumented immigrants convicted of violent crimes, human smuggling, gang/organized crime activity, sexual-related offenses, narcotics smuggling and money laundering.” Nationally, over 72 jurisdictions have implemented section 287(g) agreements in 23 states. More than 1,240 active 287(g) officers have been trained and certified, and since 2006, federal funding to facilitate 287(g) agreements has increased dramatically every year, growing from $5 million allocated in 2006 to more than $68 million in 2010 [1]. The section 287(g) program is criticized for its unintended impact on individual rights and liberties. According to reports, local officials are misusing their authority to enforce federal immigration law given to them through the program, by focusing more on minor offenses (such as traffic violations) rather than serious crimes [2]. It also has been associated with ethnic profiling and discrimination in traffic stops and through the use of checkpoints in heavily Latino enclaves (Figure 1) [3]. The section 287(g) program is one of ICE’s top partnership initiatives with local authorities. However, unlike other U.S. ICE initiatives, which limit local law enforcement immigration, Section 287(g) has a direct impact within communities. Local law-enforcement agents, such as police officers, are deputized to enforce immigration laws in their jurisdiction and without regard to civil or criminal misbehavior or suspicion [4]. Figure 1 Police set up a checkpoint in front of Latino-owned grocery store. Winston-Salem, North Carolina, U.S. (2012) Little is known about how the 287(g) program has affected willingness to seek public health services among Latino immigrants. However, based on previous research on immigration policies and access to health services [5-7], there is legitimate concern that people who are potentially subject to 287(g) enforcement, whether documented or undocumented, may refrain from seeking vital services, including medical, from any local government or private agency – even agencies unrelated to law enforcement – for fear of exposing themselves or their family members to legal sanctions or harassment. Although funding increases may be leveling off in the future, some jurisdictions are still considering whether to adopt 287(g) programs. Furthermore, other jurisdictions that have adopted 287(g) are considering whether to drop their participation, based on a concern that the burdens and costs may outweigh the perceived benefits to the community or its leaders. Timely information about the 287(g) program’s impact on public health concerns could critically inform these ongoing community participation decisions. Documenting the experiences of the 287(g) program could help inform similar debates nationally regarding local enforcement of federal immigration laws. Finally, a better understanding of whether and how immigration enforcement affects ability to seeking public health services could help to mitigate public health harms under ongoing enforcement programs.

Sobriety Checkpoints: Evidence of Effectiveness Is Strong, but Use Is Limited

There is substantial and consistent evidence from research that highly publicized, highly visible, and frequent sobriety checkpoints in the United States reduce impaired driving fatal crashes by 18% to 24%. Although checkpoints are not conducted in 13 states for legal or policy reasons, there is strong evidence that if conducted appropriately, checkpoints would save lives in the other states. However, a recent survey of checkpoint use has demonstrated that despite the efforts of the U.S. Department of Transportation to encourage checkpoint use through publications, providing funds for equipment, and for officer overtime expenses, only about a dozen of the 37 states that conduct checkpoints do so on a weekly basis. The survey found that lack of local police resources and funding, lack of support by task forces and citizen activists, and the perception that checkpoints are not productive or cost effective are the main reasons for their infrequent use. This article discusses each of these problems and suggests a method for local communities to implement checkpoints without depending on state or federal funds. Low-staffing sobriety checkpoints conducted by as few as three to five officers have been shown to be just as effective as checkpoints conducted by 15 or more officers. A modified sobriety checkpoint program using passive alcohol sensors (“PASpoints”) can be implemented by small- to moderate-sized communities in the United States to deter impaired driving. If implemented in a majority of communities, this strategy has a potential level of effectiveness similar to the high level achieved by several Australian states in their random breath-test (RBT) programs. The PASpoint system calls for a small group of three to five officers on traffic patrol duty to converge on a preset site and conduct a mini-checkpoint, returning to their standard patrol duties within two hours. Within this framework, the PASpoint operation would become a standard driving under the influence (DUI) enforcement technique regularly used within the community's jurisdiction. As a standard traffic enforcement activity, the cost would be covered by the normal enforcement budget.

Why are sobriety checkpoints not widely adopted as an enforcement strategy in the United States?

Sobriety checkpoints have been used by police in the United States for at least the past two decades to enforce impaired driving laws. Research has indicated that sobriety checkpoints are effective in reducing drinking and driving and alcohol-related fatal crashes. Despite this evidence, many police agencies have been unenthusiastic about using checkpoints. Information was collected from all 50 states plus the District of Columbia on the use of sobriety checkpoints. A total of 37 states and the District of Columbia reported conducting sobriety checkpoints at least once or twice during the year. Only 11 states reported that checkpoints were conducted on a weekly basis. Thirteen states do not conduct checkpoints either because of legal or policy issues. More detailed information was collected from five states that conduct checkpoints frequently and matched with information from five similar states that conduct checkpoints infrequently. States with frequent checkpoint programs had several common features such as program themes, support from task forces and citizen activist groups, use of a moderate number of police at the checkpoints, and use of all available funding mechanisms (federal, state, local) to support them. States with infrequent checkpoints claimed a lack of funding and police resources for not conducting more checkpoints, preferred saturation patrols over checkpoints because they were more “productive,” and used large numbers of police officers at checkpoints. Ways to overcome perceived barriers to checkpoint use are discussed.

Cheap Newton steps for optimal control problems: automatic differentiation and Pantoja's algorithm

In this paper we discuss Pantoja's construction of the Newton direction for discrete time optimal control problems. We show that automatic differentiation (AD) techniques can be used to calculate the Newton direction accurately, without requiring extensive re-writing of user code, and at a surprisingly low computational cost: for an N-step problem with p control variables and q state variables at each step, the worst case cost is 6(p + q + 1) times the computational cost of a single target function evaluation, independent of N, together with at most p 3/3 + p 2(q + 1) + 2p(q + 1)2 + (q + l)3, i.e. less than (p + q + l)3, floating point multiply-and-add operations per time step. These costs may be considerably reduced if there is significant structural sparsity in the problem dynamics. The systematic use of checkpointing roughly doubles the operation counts, but reduces the total space cost to the order of 4pN floating point stores. A naive approach to finding the Newton step would require the solution of an Np × Np system of equations together with a number of function evaluations proportional to Np, so this approach to Pantoja's construction is extremely attractive, especially if q is very small relative to N. Straightforward modifications of the AD algorithms proposed here can be used to implement other discrete time optimal control solution techniques, such as differential dynamic programming (DDP), which use state-control feedback. The same techniques also can be used to determine with certainty, at the cost of a single Newton direction calculation, whether or not the Hessian of the target function is sufficiently positive definite at a point of interest. This allows computationally cheap post-hoc verification that a second-order minimum has been reached to a given accuracy, regardless of what method has been used to obtain it.

The development of an approach to evaluate NHS manager's competence in medical informatics

This paper describes the research and development of Checkpoint, a self-assessment instrument. It outlines how the instrument has helped managers in the NHS identify their strengths and weaknesses with respect to their management and use of informatics. The paper presents trends and feedback from the use of Checkpoint and the implications for future education and training of managers in the NHS.

Distributed Breakpoint Detection in Message-Passing Programs

The ability to set breakpoints stands, along with the possibility of deterministic reexecution, as one of the most important issues in the debugging of message-passing programs. We consider in this paper the design of fully distributed algorithms for the detection of breakpoints in such programs, and provide four algorithms, one for each different type of breakpoint. One of the algorithms detects the occurrence of unconditional breakpoints, while the other three detect the occurrence of breakpoints on disjunctive predicates, stable conjunctive predicates, and generic conjunctive predicates. All the algorithms we present detect breakpoints in the form of earliest global states with respect to the particular property involved. In the case of unconditional breakpoints, such an earliest global state must coincide exactly with the requested local unconditional breakpoints for the processes that do actually participate in the breakpoint. In the case of the other (conditional) breakpoints, what is detected is the earliest global state at which either the disjunctive or the conjunctive predicate under consideration is true. In order to actually halt the computation at the exact global state the algorithms detect, we suggest as a first approach the use of checkpointing and rollback-recovery techniques.

Process checkpointin primitives for fault tolerance: definitions and examples

Many fault tolerance techniques that are implemented via software are based on the use of process checkpointing and restore primitives. This is true both for methods used in system fault tolerance and for methods used in software fault tolerance, such as Recovery Blocks, but usually system and software fault tolerance appear to require different ad hoc primitives. Moreover, the use of checkpointing primitives within components implementing different kinds of fault tolerance should be coordinated, to save space and time. In this paper we present a unified interface for checkpointing and restore primitives, which is suitable both for software and for system fault tolerance in UNIX-type systems. We provide examples of the use of such primitives, including the use in a dedicated software component (the Recovery Meta Program) which may implement various techniques for fault tolerance. Finally, we discuss the implementation of the proposed primitives, and provide a comparison with some complementary approaches.

A legal analysis of sobriety checkpoints

Law enforcement agents are asked to help solve problems involving alcohol abuse in a society exhibiting reluctance to change its attitude about drinking and driving. As the public’s concern over drunken driving intensifies, use of the sobriety checkpoint is becoming a major law enforcement/public policy issue. Recent case law upholds use of the checkpoint in order to deter and detect the drunken driver. Although the United States Supreme Court has not directly ruled on the constitutionality of the sobriety checkpoint, there is a considerable body of state case law upholding its validity. Generally, with some exceptions, sobriety checkpoints appear to be constitutional if law enforcement agents follow proper guidelines and procedures. This paper analyzes case law pertaining to checkpoints, and gives law enforcement agencies direction in establishing constitutionally sound sobriety checkpoints, in conclusion, the article synthesizes roadblock and sobriety checkpoint law to provide law enforcement officers a plan for proper checkpoint construction.