Dynamic Instrumentation Research Articles

Lub: A pattern for fine grained behavior adaptation at runtime

• We present Lub, an object-oriented pattern for fine grained unanticipated adaptation. • We discuss the difficulties of unanticipated adaptation. • We evaluate Lub on a simulation with a fleet of drones which is dynamically adapted. • The Lub pattern is discussed in regard to the literature. Autonomous systems have to evolve in complex environments and their software must adapt to various situations. Although it is common to anticipate adaptations at design time, it becomes a more complex issue when facing unpredictable contexts at runtime, especially if applications cannot be stopped. We introduce Lub, a pattern designed to extend object oriented languages with fine grained unanticipated adaptations. Lub is based on dynamic instrumentation of the lookup, and allows objects to acquire behaviors from another class than their own. A Pharo Smalltalk implementation of Lub is evaluated through a performance analysis and a running example of a fleet of drones facing unexpected GPS problems. Lub is then discussed from the unanticipated software adaptation perspective.

Bringing Assessment of Patient-Reported Outcomes to Hepatology Practice

Bringing Assessment of Patient-Reported Outcomes to Hepatology Practice

A new in vitro spine test rig to track multiple vertebral motions under physiological conditions.

In vitro pure moment spine tests are commonly used to analyse surgical implants in cadaveric models. Most of the tests are performed at room temperature. However, some new dynamic instrumentation devices and soft tissues show temperature-dependent material properties. Therefore, the aim of this study is to develop a new test rig, which allows applying pure moments on lumbar spine specimens in a vapour-filled chamber at body temperature. As no direct sight is given in the vapour-filled closed chamber, a magnetic tracking (MT) system with implantable receivers was used. Four human cadaveric lumbar spines (L2-L5) were tested in a vapour atmosphere at body temperature with a native and rigid instrumented group. In conclusion, the experimental set-up allows vertebral motion tracking of multiple functional spinal units (FSUs) in a moisture environment at body temperature.

Use of Minimal Invasive Technique in Dynamic Hip Screw Fixation

Among different implants like Proximal Femoral Nailing, Dynamic Hip Screw, Proximal Femoral Locking Plate used in fixation of intertrochanteric fracture, minimally invasive Dynamic Hip Screw has several advantages. Surgeons treating patients with low economic resource with surgical co-morbidity could not routinely use less invasive imported implants due to high cost or poor quality of local intramedullary implants. Minimal Invasive Dynamic Hip Screw will be the possible solution. Minimal Invasive Dynamic Hip Screw has several advantages like short learning curve, 4 times shorter incision than conventional Dynamic Hip Screw, comparable outcome, less operative time, less post-operative wound care. We consider Minimal Invasive Dynamic Hip Screw as one of the cost effective technique in intertrochanteric fracture management. Patient with stable intertrochanteric fracture and with co-morbidity which limiting his/her operative time will be the ideal candidate for Minimal Invasive Dynamic Hip Screw. Most of the surgeons think special instrument sets are necessary to perform Minimal Invasive Dynamic Hip Screw but the truth is instruments used for routine fracture fixation and conventional Dynamic Hip Screw instruments are more than sufficient for Minimal Invasive Dynamic Hip Screw. In our center we routinely perform Minimal Invasive Dynamic Hip for patients with low economic resource with surgical co-morbidity could not routinely use less invasive imported implants due to high cost or poor quality of local intramedullary implants. And all patients give encouraging results in regards with early mobilization and radiographic fracture union. None of our cases had potential complications like superior cut through, implant failure, and infection. In summary Minimal Invasive Dynamic Hip Screw. technique had comparable outcome with intramedullary and conventional Dynamic Hip Screw fixation in terms of operative time, blood loss, duration of hospital stay and fracture union rate. Hence we recommend Minimal Invasive Dynamic Hip Screw. fixation technique with low economic resource patient with co-morbidities restricting operative time.

Biomechanical testing of a PEEK-based dynamic instrumentation device in a lumbar spine model

BackgroundThe purpose of this study was to investigate the range-of-motion after posterior polyetheretherketone-based rod stabilisation combined with a dynamic silicone hinge in order to compare it with titanium rigid stabilisation. MethodsFive human cadaveric lumbar spines with four vertebra each (L2 to L5) were tested in a temperature adjustable spine-testing set-up in four trials: (1) native measurement; (2) kinematics after rigid monosegmental titanium rod instrumentation with anterior intervertebral bracing of the segment L4/5; (3) kinematics after hybrid posterior polyetheretherketone rod instrumentation combined with a silicone hinge within the adjacent level (L3/4) and (4) kinematics after additional decompression with laminectomy of L4 and bilateral resection of the inferior articular processes (L3). During all steps, the specimens were loaded quasi-statically with 1°/s with pure moment up to 7.5Nm in flexion/extension, lateral bending and axial rotation. FindingsIn comparison to the native cadaveric spine, both the titanium device and polyetheretherketone-based device reduce the range-of-motion within the level L4/5 significantly (flexion/extension: reduction of 77%, p<0.001; lateral bending: reduction of 62%, p<0.001; axial rotation: reduction of 71%, p<0.001). There was a clear stabilisation effect after hybrid-instrumentation within the level L3/4, especially in flexion/extension (64%, p<0.001) and lateral bending (62%, p<0.001) but without any effect on the axial rotation. Any temperature dependency has not been observed. InterpretationSurprisingly, the hybrid device compensates for laminectomy L4 and destabilising procedure within the level L3/4 in comparison to other implants. Further studies must be performed to show its effectiveness regarding the adjacent segment instability.

Surface Level Estimator-An Automated Contouring Instrument

This paper introduces a dynamic electronic instrument to measure the inclination of a surface, named as Surface Level Estimator (SLE). This device is designed to reduce the human effort and time consumed for civil surveying. This paper describes the construction, working principle, programming and experimentation results of the instrument. Finally, the conclusion and scope of future is discussed at the end of the paper.

Hybrid Instrumentation in Lumbar Spinal Fusion: A Biomechanical Evaluation of Three Different Instrumentation Techniques.

Study DesignEx vivo human cadaveric study.ObjectiveThe development or progression of adjacent segment disease (ASD) after spine stabilization and fusion is a major problem in spine surgery. Apart from optimal balancing of the sagittal profile, dynamic instrumentation is often suggested to prevent or impede ASD. Hybrid instrumentation is used to gain stabilization while allowing motion to avoid hypermobility in the adjacent segment. In this biomechanical study, the effects of two different hybrid instrumentations on human cadaver spines were evaluated and compared with a rigid instrumentation.MethodsEighteen human cadaver spines (T11–L5) were subdivided into three groups: rigid, dynamic, and hook comprising six spines each. Clinical parameters and initial mechanical characteristics were consistent among groups. All specimens received rigid fixation from L3–L5 followed by application of a free bending load of extension and flexion. The range of motion (ROM) for every segment was evaluated. For the rigid group, further rigid fixation from L1–L5 was applied. A dynamic Elaspine system (Spinelab AG, Winterthur, Switzerland) was applied from L1 to L3 for the dynamic group, and the hook group was instrumented with additional laminar hooks at L1–L3. ROM was then evaluated again.ResultsThere was no significant difference in ROM among the three instrumentation techniques.ConclusionBased on this data, the intended advantage of a hybrid or dynamic instrumentation might not be achieved.

An improved whole-machine balancing method based on double auto-correlation measurement

The key phase signal is an important factor in the traditional whole-machine balancing method, but, sometimes, it is very hard to get that signal in the rotor system on the scene. A new method to get the unbalance component by only measuring the unbalance vibration amplitude is proposed in this paper. We discuss how to extract the rotor speed based on double auto-correlation; how to identify the unbalance vibration amplitude based on cross-correlation and the design of the special dynamic balancing instrument based on amplitude measurement. This method is also integrated in our newly developed instrument and the experiments prove it works well.

Прикладное применение динамического анализа программ, исполняющихся в интерпретирующих средах

The present-day trends in software engineering include the steady increase of code and design complexity which reinforces the high demand in automated software testing and analysis tools. In this paper, we showcase several dynamic program analysis applications and present our solutions. These applications include memory profiling, automated test generation using dynamic symbolic execution and automated detection of concurrency bugs in multithreaded programs. Our memory profiling tool is designed for Java applications for Android and it is implemented through Android Dalvik VM modification. This approach allowed us to overcome existing Dalvik VM limitations that make existing profiling tools based on dynamic bytecode instrumentation inaccessible. We have successfully applied our tool to several core Android applications - the results provided in the paper outline the effectiveness of the approach. The second solution we discuss in the paper - dynamic symbolic execution for test generation automation - allows us to efficiently generate test scenarios for Java program graphical user interface. The core technologies of the approach include the use of static bytecode instrumentation and automatic GUI model extraction. We implement the approach on top of a user interface test automation framework GUITAR. Finally, we present our approach to automatically identify concurrency bugs in multithreaded Java applications. The approach is based on static bytecode instrumentation for trace generation and employs ThreadSanitizer defect detection tool for identifying bugs.

COMPARATIVE STUDY ON THE TREATMENT OF DISC HERNIATIONS

ABSTRACT Objective: To compare the results of treatment of patients with low back pain and radiculalgia resulting from disc herniation associated with disc degeneration through instrumentation with pedicle screws and dynamic rod, with root release and without diskectomy compared with other non-instrumented techniques (microdiskectomy with or without foraminotomy). Methods: This is a retrospective descriptive study of interventions for patients with herniated discs in the Traumatology and Neurosurgery that used the following variables: age, sex, type of technique, surgical time, time of evolution, degree of satisfaction, and complications. Two groups were formed: instrumentation with dynamic rods and non-instrumented techniques, comparing the results of each group. The software used was the SPSS v20.0. Results: We presented 142 interventions carried out between 2009 and 2012, 86 with dynamic instrumentation and 56 by other decompression techniques without instrumentation. No statistically significant differences were observed between age and sex groups and time elapsed until intervention. We found statistically significant differences (p=0.001) in surgical time, which was lower in the instrumented technique. No significant differences were found in complications between the techniques in both re-operations and in infections. Conclusions: In this study, we found no significant differences between the use of instrumentation with dynamic rods with respect to other non-instrumented surgical techniques in the treatment of herniated discs over 6 months of evolution or the complications and the degree of the patients' satisfaction.

Indoor footstep localization from structural dynamics instrumentation

Measurements from accelerometers originally deployed to measure a building's structural dynamics can serve a new role: locating individuals moving within a building. Specifically, this paper proposes measurements of footstep-generated vibrations as a novel source of information for localization. The complexity of wave propagation in a building (e.g., dispersion and reflection) limits the utility of existing algorithms designed to locate, for example, the source of sound in a room or radio waves in free space. This paper develops enhancements for arrival time determination and time difference of arrival localization in order to address the complexities posed by wave propagation within a building's structure. Experiments with actual measurements from an instrumented public building demonstrate the potential of locating footsteps to sub-meter accuracy. Furthermore, this paper explains how to forecast performance in other buildings with different sensor configurations. This localization capability holds the potential to assist public safety agencies in building evacuation and incidence response, to facilitate occupancy-based optimization of heating or cooling and to inform facility security.

Fuzzing binaries with Lévy flight swarms

We present a new method for random testing of binary executables inspired by biology. In our approach, we introduce the first fuzzer based on a mathematical model for optimal foraging. To minimize search time for possible vulnerabilities, we generate test cases with Levy flights in the input space. In order to dynamically adapt test generation behavior to actual path exploration performance, we define a suitable measure for quality evaluation of test cases. This measure takes into account previously discovered code regions and allows us to construct a feedback mechanism. By controlling diffusivity of the test case generating Levy processes with evaluation feedback from dynamic instrumentation, we are able to define a fully self-adaptive fuzzing algorithm. We aggregate multiple instances of such Levy flights to fuzzing swarms which reveal flexible, robust, decentralized, and self-organized behavior.

Validity and Predictive Accuracy of the Structured Assessment of Protective Factors for Violence Risk in Criminal Forensic Evaluations

Some actuarial and structured professional judgment (SPJ) risk-assessment instruments have already demonstrated their validity and predictive accuracy in expert criminal forensic evaluations. In contrast, little is known about the effectiveness of instruments identifying protective factors in risk of recidivism prediction. The present study was designed to evaluate the validity and predictive accuracy of the Structured Assessment of Protective Factors for Violence Risk (SAPROF) in 94 violent and sexual violent offenders assessed in a Swiss pretrial criminal forensic context. The SAPROF showed good interrater reliability, and was significantly correlated to predominately dynamic instruments but not to predominately actuarial instruments. However, in terms of predictive accuracy, the SAPROF did not perform as well as expected when compared with other instruments and with previous SAPROF accuracy validation studies. These results have implications for the use of the SAPROF in criminal forensic contexts risk assessment.

Improving risk management for violence in mental health services: a multimethods approach

BackgroundMental health professionals increasingly carry out risk assessments to prevent future violence by their patients. However, there are problems with accuracy and these assessments do not always translate into successful risk management.ObjectivesOur aim was to improve the accuracy of assessment and identify risk factors that are causal to be targeted by clinicians to ensure good risk management. Our objectives were to investigate key risks at the population level, construct new static and dynamic instruments, test validity and construct new models of risk management using Bayesian networks.Methods and resultsWe utilised existing data sets from two national and commissioned a survey to identify risk factors at the population level. We confirmed that certain mental health factors previously thought to convey risk were important in future assessments and excluded others from subsequent parts of the study. Using a first-episode psychosis cohort, we constructed a risk assessment instrument for men and women and showed important sex differences in pathways to violence. We included a 1-year follow-up of patients discharged from medium secure services and validated a previously developed risk assessment guide, the Medium Security Recidivism Assessment Guide (MSRAG). We found that it is essential to combine ratings from static instruments such as the MSRAG with dynamic risk factors. Static levels of risk have important modifying effects on dynamic risk factors for their effects on violence and we further demonstrated this using a sample of released prisoners to construct risk assessment instruments for violence, robbery, drugs and acquisitive convictions. We constructed a preliminary instrument including dynamic risk measures and validated this in a second large data set of released prisoners. Finally, we incorporated findings from the follow-up of psychiatric patients discharged from medium secure services and two samples of released prisoners to construct Bayesian models to guide clinicians in risk management.ConclusionsRisk factors for violence identified at the population level, including paranoid delusions and anxiety disorder, should be integrated in risk assessments together with established high-risk psychiatric morbidity such as substance misuse and antisocial personality disorder. The incorporation of dynamic factors resulted in improved accuracy, especially when combined in assessments using actuarial measures to obtain levels of risk using static factors. It is important to continue developing dynamic risk and protective measures with the aim of identifying factors that are causally related to violence. Only causal factors should be targeted in violence prevention interventions. Bayesian networks show considerable promise in developing software for clinicians to identify targets for intervention in the field. The Bayesian models developed in this programme are at the prototypical stage and require further programmer development into applications for use on tablets. These should be further tested in the field and then compared with structured professional judgement in a randomised controlled trial in terms of their effectiveness in preventing future violence.FundingThe National Institute for Health Research Programme Grants for Applied Research programme.

Item Response Theory and Computerized Adaptive Testing for Orthopaedic Outcomes Measures.

The use of patient-reported outcome measures (PROMs) to objectively and quantifiably assess patient symptomatology allows tracking of symptoms over time, measurement of the effect of healthcare interventions, and performance of cost-effectiveness analyses to assess and compare the value of treatment options. Many of the PROMs historically used had limited versatility because they were developed using classical test theory, which generates static tests that are not comparable with other measures assessing similar outcomes. Recently developed PROMs, however, were designed according to the principles of the newer item response theory (IRT), which allows for the creation of dynamic instruments deliverable in a variety of forms that are readily comparable with similar measures. IRT also enables computerized adaptive testing to decrease the burden of using PROMs by allowing rapid and complete data acquisition. IRT-based instruments are suitable for patient care and research and have been validated in a variety of populations, many of which are relevant to orthopaedic populations.

Management of Supracondylar Femoral Fractures by Retrograde Nailing Technique: A Retrospective and Prospective Study

Objectives: The goal of our study is to study the management of supracondylar fractures of femur by retrograde intramedullary nailing and its clinical and functional outcome. Methods/ Statistical Analysis: The study was done on patient with distal femur fractures. The patient ranged from 18–85yrs of age. Patient below 16yrs of age and Pathological fractures were excluded. All the patients were treated according to a protocol. Investigations were done, patient’s general condition was assessed and fitness for surgery was taken. Patients were managed by closed reduction and internal fixation under C-arm or by open reduction and internal fixation using tourniquet. Patient was followed with clinical and x-ray findings. Findings: Closed fractures managed by closed technique have a better result with significance. When compared between the shortening and surgical technique, the open reduction techniques are associated with more shortening compared to closed reduction technique and this appears to be statistically significant in our study. Conclusion: Retrograde intramedullary nail is a dynamic instrument and still persists as a major option for treatment of distal femoral fracture despite recent advances in the management of fracture.

Thermal Radiation Measurement With Thermoresistive Sigma–Delta Modulator

This paper presents a radiometer project based on a sigma–delta modulator. A model of the static and dynamic instrument behavior is made, relating the parameters of a sensor/heater to noise and measurement error. It is shown that the output binary code has a linear relationship with the power being measured independent of the sensor’s nonlinearity. Experimental results obtained from a prototype ratify the results predicted by modeling, showing that this approach can be useful as a basis for generating a digital output related to the unknown power.

Nas trilhas da utopia: tecendo o projeto político-pedagógico em um curso de nutrição

Resumo O projeto político-pedagógico surge como um instrumento dinamizador das mudanças desejadas e necessárias para a formação de profissionais de saúde, em articulação com a organização do sistema de saúde e visando à integralidade da assistência e à superação da fragmentação característica do paradigma biomédico. O objetivo deste estudo foi lançar um olhar sobre a formação em um curso de nutrição com base nas representações discentes sobre as potencialidades e fragilidades do projeto político-pedagógico instituinte, em diálogo com o projeto instituído. Realizaram-se grupos focais com 46 estudantes. Os dados assim coletados foram tratados por análise de conteúdo, e sua interpretação subsidiada pelo projeto político--pedagógico instituído do curso. Formação e atuação docentes, disciplinas articuladoras, metodologia do trabalho de conclusão, contato precoce com a prática e realização de seminários pedagógicos emergiram como potencialidades do processo de formação. A reduzida presença de docentes nutricionistas nas fases iniciais e a falta de contextualização de algumas disciplinas foram as fragilidades apontadas. Concluiu-se, das potencialidades e fragilidades indicadas, que avanços importantes têm sido conquistados na direção do perfil desejado para o egresso. Resta como desafio buscar um processo de formação docente que possa produzir um novo salto qualitativo de aproximação entre instituído e instituinte.

Design and implementation of user-level dynamic binary instrumentation on ARM architecture

We have developed a user-level dynamic binary instrumentation (DBI) tool on ARM architecture to enable applying various analysis techniques such as performance evaluation, profiling, and bug detection. Most of existing DBI tools are based on the x86 architecture. As demands for the similar approaches mainly performed in x86 are getting higher in an embedded device domain as well, DBI environment is strongly required for embedded devices especially ARM architecture which has a majority of market share in embedded systems. Only a few tools are currently available to ARM but they are very limited to a specific purpose. Therefore, we designed and implemented a general-purpose DBI tool on ARM to execute an arbitrary code between instructions of a target process. Our tool supports native execution environment which is required for security analysis. We have conducted some experiments with common UNIX utilities and an Android application to validate our tool by tracing and saving context information of every instruction of a desired thread. As a result, we have confirmed that it works as expected without affecting the original context of the target process.

Preparation of Shape Memory NiTiNOL Filaments for Smart Textiles

A nickel-titanium alloy (NiTiNOL, nitinol) fi lament with a diameter of 200 μm was used for preparing a smart knitted textile fabric with a shape memory eff ect within the range of human body temperatures. The annealing of the fi lament at 500 °C for 30 minutes was followed by air cooling at 20 °C to achieve a suitable transition temperature from martensite to austenite phase within the range between room temperature and 75 °C. The tensile properties of fi laments before annealing and after it were analysed on Instron 6022 dynamometer. The measurements of exact transition temperatures from soft martensite state at room temperature to hard austenite state at heating were made on a dynamic mechanical analysis instrument. From the annealed fi lament a left-right knitted fabric was hand made. The fabric was trained into a selected 3D form by cyclic heating in a strained form at 75 °C for 10 minutes and then cooled at room temperature. For a stable two-way memory eff ect, the nitinol fabric needed to make fi fteen cycles of heating and cooling.