Showing papers in "Insight in 2016"

Fault diagnosis of industrial robot gears based on discrete wavelet transform and artificial neural network

Abstract: Industrial robots have long been used in production systems in order to improve productivity, quality and safety in automated manufacturing processes. An unforeseen robot stoppage due to different reasons has the potential to cause an interruption in the entire production line, resulting in economic and production losses. The majority of the previous research on industrial robots health monitoring is focused on monitoring of a limited number of faults, such as backlash in gears, but does not diagnose the other gear and bearing faults. Thus, the main aim of this research is to develop an intelligent condition monitoring system to diagnose the most common faults that could be progressed in the bearings of industrial robot joints, such as inner/outer race bearing faults, using vibration signal analysis. For accurate fault diagnosis, time-frequency signal analysis based on the discrete wavelet transform (DWT) is adopted to extract the most salient features related to faults, and the artificial neural network (ANN) is used for faults classification. A data acquisition system based on National Instruments (NI) software and hardware was developed for robot vibration analysis and feature extraction. An experimental investigation was accomplished using the PUMA 560 robot. Firstly, vibration signals are captured from the robot when it is moving one joint cyclically. Then, by utilising the wavelet transform, signals are decomposed into multi-band frequency levels starting from higher to lower frequencies. For each of these levels the standard deviation feature is computed and used to design, train and test the proposed neural network. The developed system has showed high reliability in diagnosing several seeded faults in the robot.

Technology Update on the Unified Architecture Framework (UAF)

Abstract: Architecture frameworks continue to evolve. The Unified Profile for the Department of Defense (DoD) Architecture Framework (DoDAF) and the UK's Ministry of Defence Architecture Framework (MODAF) (UPDM) provides a standard means of representing DoDAF, MODAF, and NATO Architecture Framework (NAF) conformant architectures using the Unified Modeling Language (UML), and Systems Modeling Language (SysML). Since the UPDM V2.0 publication, further information has emerged such as the June 2011 NATO study entitled: “Development of The AMN (Afghanistan Mission Network) Architecture In 2010 – Lessons Learned,” by Torsten Graeber of the NATO C3 Agency. This report identified the following in section 4.1-ARCHITECTURE FRAMEWORKS, sub-section 4.1.2 Observations (Need for a Unified Architecture Framework) and stated that: • differences in DoDAF, MODAF, and NAF make it difficult to match the metamodel one to one. • some of the concepts in the frameworks have the same name but different definitions, i.e. different semantics. • difficult to cross-walk the concepts between the different frameworks leads to miscommunication between architects using different frameworks. Based on the above, the NATO Architecture Capability Team (Architecture CaT) meeting on Sept. 10-11, 2012 committed to move to a single world-wide Architecture Framework. Consequently, a new architecture framework profile supporting a unified framework is needed. It is intended that this framework bring the different architecture frameworks together. The UPDM V3.0 domain metamodel shall be derived from MODEM (the MODAF metamodel) and the DoDAF 2.0 metamodel (DM2), both of which are based upon the International Defence Enterprise Architecture Specification Foundation [IDEAS]. This paper will document the rationale behind the UPDM 3.0 as well as its new name of the Unified Architecture Framework (UAF).

Systems of systems, cyber‐physical systems, the internet‐of‐things…whatever next?

Abstract: This paper considers the concepts of systems of systems, cyber-physical systems, and the Internet-of-things. Although originating from different domains and perspectives, there is considerable convergence of the three concepts in terms of future complex systems, and it is concluded that the Internet-of-things is essentially a cyber-physical system of systems which will require new approaches in systems engineering to be developed.

Novel spectral kurtosis technology for adaptive vibration condition monitoring of multi-stage gearboxes

Abstract: In this paper, novel Wavelet Spectral Kurtosis (WSK) technique is applied for early diagnosis of gear tooth faults. Two variants of Wavelet Spectral Kurtosis technique called Variable Resolution WSK and Constant Resolution WSK are considered for diagnosis of the pitting gear fault. The gear residual signal obtained by filtering the gear mesh frequencies is used as the input to the SK algorithm. The gain obtained by using the wavelet SK techniques when compared to classical Fourier Transform (FT) based SK, is confirmed by estimating tooth wise Fisher’s Criterion of diagnostic features. The final diagnosis decision is made by a three stage decision making technique based on weighted majority rule. The probability of the correct diagnosis is estimated for each SK technique for comparison. An experimental study is presented in detail to test the performance of the wavelet spectral kurtosis techniques and the decision making technique.

Sonic and ultrasonic measurement applications for cased oil wells

Abstract: Elastic waves have numerous oilfield applications, most pertinently for well integrity characterization of cased wells. The measurements are used to determine the quality of cement placed between the casing and formation rock or between multiple casing or liner strings. In addition to supporting the casing and protecting it from corrosive fluids, the cement is placed to prevent hydraulic communication between formation layers that were isolated from each other before the well was drilled. This talk focuses on low-frequency sonic measurements and high-frequency ultrasonic measurements that are currently used or in development for cement evaluation. The domain has seen tangible progress with advances in the understanding of the physics related to the measurements and the development of effective modeling, signal processing, inversion, and interpretation methodologies. The measurements leverage the physics associated with the guided waves excited in the casing string that propagate axially along the direction of the borehole. Signal processing and interpretation rely on phase or dispersion information as well as time of flight and amplitude variations across receivers to provide a diagnosis of cement quality and an estimation of the material properties of interest.

Introduction to systems of systems engineering

Abstract: This article provides an introduction and overview of basic concepts of ‘systems of systems’ (SoS). Beginning with the definition of SoS and SoS engineering, the paper describes the characteristics of SoS. It compares systems with SoS and discusses the implications for systems engineering. Finally, the paper concludes with a discussion of the challenges SoS pose for systems engineering with a description of recognized SoS ‘pain points.

KESEJAHTERAAN PSIKOLOGIS (PSYCHOLOGICAL WELL-BEING) SISWA YANG ORANGTUANYA BERCERAI(Studi Deskriptif yang Dilakukan pada Siswa di SMK Negeri 26 Pembangunan Jakarta)

Abstract: Tujuan penelitian ini adalah mengetahui kesejahteraan psikologis siswa yang orangtuanya bercerai di SMK Negeri 26 Pembangunan Jakarta. Sampel penelitian ini adalah 33 siswa yang memiliki latar belakang orangtua bercerai. Teknik yang digunakan dalam pengambilan sampel ini adalah teknik sampling jenuh. Pengumpulan data dilakukan dengan menggunakan kuesioner kesejahteraan psikologis. Hasil uji validitas didapatkan 46 butir pernyataan valid dan 22 butir pernyataan yang drop. Uji reliabilitas dari instrumen ini didapat sebesar 0.928 yang berarti instrumen ini memiliki reliabilitas tinggi dan dapat dipercaya. Hasil penelitian ini menunjukkan bahwa 52% siswa memiliki kesejahteraan psikologis yang rendah, sebesar 42% siswa memiliki kesejahteraan psikologis yang tinggi, dan 6% siswa memiliki kesejahteraan psikologis yang sedang/ cukup. Kesejahteraan psikologis siswa yang orangtuanya bercerai pada penelitian ini berada dalam taraf rendah yang berarti perlu adanya penanganan lebih lanjut agar kesejahteraan psikologis siswa menjadi tinggi. Jika siswa yang orangtuanya bercerai memiliki kesejahteraan psikologis yang tinggi dalam hal ini maka dapat membantu siswa dalam melewati tugas-tugas perkembangan, menghadapi tantangan, menjalankan hidupnya dengan bahagia, tenang dan mampu mengatasi segala masalah yang dihadapi.

Rotating machine diagnosis using smart feature selection under non-stationary operating conditions

Abstract: Fluctuating operating load and speed conditions are found in many industrial applications and the standard condition monitoring techniques for stationary systems are often inadequate for accurately detecting and diagnosing faults under such conditions. Discrepancy analysis has been proposed to deal with such issues. The idea of discrepancy analysis is based on the similar concept of residual analysis where all healthy vibration components, such as meshing frequency and its harmonics, are removed from the signal, leaving only the damage related vibration components. However the discrepancy signal does not physically remove the vibration components. Instead, by statistically comparing a novel signal to a reference model, the discrepancy signal is formed by its likelihood with respect to the reference model. Since the reference model is solely based on a healthy system, any discrepancy is assumed to be purely as a result of the presence of a fault. By allowing the empirical model to take the non-stationary operating conditions into account, the effects of fluctuating load and speed can be removed as well. Thus the discrepancy signal significantly reduces the complexity of fault detection and enables the type and severity of the fault to be determined using standard signal processing techniques. To classify the operating conditions and detect the presence of a fault it is necessary to create statistical and classification models. These models are trained on data measured on the healthy systems over the full range of expected operating conditions. A novel signal can then be piecewise evaluated against the reference models in order to detect instantaneous deviations. These deviations are indicative of gear faults. This work offers a new method for detecting, diagnosing and determining the severity of faults in gearboxes under non-stationary operating conditions that are independent of historical fault data and not reliant on measures of either operating speed or load.

PENGARUH TERAPI EXPRESSIVE WRITING TERHADAP PENURUNAN KECEMASAN SAAT UJIAN SEKOLAH(Studi Kuasi Eksperimen Terhadap Siswa Kelas XI di SMA Negeri 59 Jakarta)

Abstract: Tujuan penelitian ini untuk mengetahui pengaruh expressive writing terhadap penurunan tingkat kecemasan tinggi pada siswa saat ujian sekolah. Penelitian ini dilakukan di SMA Negeri 59 Jakarta pada bulan Agustus sampai dengan September 2015. Penelitian ini menggunakan peneliti kuasi eksperimen dengan bentuk Nonequivalent Control Group Design. Berdasarkan hasil uji validitas dan reliabilitas yang telah digunakan, instrumen kecemasan memiliki 62 item butir pernyataan yang valid dan memiliki koefisien reliabilitas sebesar 0.933. Berdasarkan hasil pengujian hipotesis dengan menggunakan teknik Wilcoxon Match Pairs Test, diperoleh nilai Asymp. Sig sebesar 0.01 yang berarti nilai probabilitas lebih kecil dari nilai signifikansi α 0.05, maka terjadinya penururan kecemasan pada siswa dengan melakukan expressive writing. Dengan demikian dapat disimpulkan bahwa H0 ditolak dan H1 diterima, yaitu dengan terjadinya penurunan tingkat kecemasan tinggi bagi siswa saat ujian sekolah yang signifikan setelah diberikan perlakuan. Terapi expressive writing dapat diterapkan oleh guru bimbingan dan konseling di sekolah sebagai salah salah satu alternatif penanganan untuk menangani siswa yang mengalami masalah dengan tingginya tingkat kecemasan saat ujian sekolah

Examination of Barkhausen noise parameters for characterisation of strain-induced martensitic transformation in AISI 304 stainless steel

Abstract: In this study, the strain-induced martensitic transformation in AISI 304 stainless steel after tensile deformation was investigated using different magnetic Barkhausen noise (MBN) parameters. For this purpose, different amounts of martensite phase were formed in AISI 304 stainless steel by different amounts of tensile deformation. The amount of strain-induced martensite phase in the steel samples was quantified by XRD patterns. The MBN profile and the RMS voltage of the MBN parameters were employed in order to evaluate the microstructural changes. The MBN parameters (RMS and peak height) increased with the amount of deformation and this was attributed to the volume fraction of magnetic domains and pinning sites increasing with the increase in martensite content. It was suggested that the growth of martensite laths provided wider areas for the motion of domain walls and their interaction with obstacles within the martensite, resulting in an increasing rate of change in the RMS values and the width of the MBN profile with martensite content. However, the coalescence of martensite packets decreased the number of Barkhausen signals being emitted from the austenite-martensite interface areas, resulting in a decrease in the slope of the peak height curve with increasing martensite content.

System‐aware cyber security: a systems engineering approach for enhancing cyber security

Abstract:  ABSTRACT This article highlights the importance of concurrently addressing process, people, and technology factors when conducting research related to new systems engineering concepts. In particular, an ongoing US Department of Defense-sponsored, University of Virginia-led cyber security research project is used as an example of how concurrent research activities provide value earlier in the technology design phase than otherwise would have occurred. The example project focuses on adding a new layer of protection for computer-controlled physical systems. Through concurrent efforts, the research team developed a better a protection approach, resulting in better prospects for transition into use.

A foundation for developing sustainably secure systems

Abstract: This article is intended to introduce and familiarize systems engineers with ongoing developments in the field of systems security engineering and particularly the effort to develop NIST Special Publication 800-160 Systems Security Engineering, which provides security considerations for engineering trustworthy secure systems.

Profil permasalahan siswa sekolah menengah pertama (smp) negeri di kota bogor

Abstract: Tujuan penelitian ini adalah untuk mengetahui gambaran permasalahan siswa SMP Negeri di Kota Bogor. Populasi penelitian berjumlah 16228 siswa dengan menggunakan teknik sampling insidental dan jumlah sampel yang diambil 386 siswa. Instrumen yang digunakan dalam penelitian ini adalah kuesioner. Uji coba instrumen dalam penelitian ini adalah uji validitas dan uji reliabilitas. Uji validitas butir instrumen penelitian menggunakan rumus korelasi product moment. Hasil uji validitas 120 butir pernyataan dengan kriteria r-tabel yang digunakan sebesar 0,28 menghasilkan butir yang valid 94 butir dan 26 butir yang drop. Uji reliabilitas dengan teknik uji administrasi sederhana menggunakan rumus Alpha Cronbach dan di dapatkan hasil 0,92 yang berarti bahwa instrumen memiliki reliabilitas tinggi. Analisis dalam penelitian ini dilakukan secara deskriptif kuantitatif untuk mengetahui tingkat permasalahan siswa kemudian mengkategorisasikannya dalam kategori sangat bermasalah, bermasalah dan tidak bermasalah. Hasil penelitian menunjukkan bahwa siswa SMP Negeri di Kota Bogor masuk dalam kategori bermasalah (62.44%). Dengan demikian guru bimbingan dan konseling dapat segera memberikan layanan secara preventif dan kuratif secara komprehensif yakni layanan dasar, layanan responsif, perencanaan individual, dan dukungan sistem kepada seluruh siswa, terutama siswa yang bermasalah.