Sensitivity analysis in statistics

Statistical models are simplification of reality; we rarely expect the model to be exactly true. Nevertheless, when we select a statistical technique and a perform statistical inference, we often act as if the model is true. This is often justified by claiming that "small" deviations from the model cause only "small" deviations from the theoretical properties of the selected inferential techniques or cause only minor changes in the results produced by the inference. U nfortunately, th is argument need not be trlle. In some appl ications apparently small changes in a model. a 11l0del asslImption, or a data point, can have very large effects on the results. For this reason, statistical analysis is viewed in this paper as a cyclical process. Such a process takes inputs and produces outputs in an iterative or cyclical way; a way in which the outputs can be used to diagnose, validate, criticise, and possibly alter the inputs. We also describe a general framework, referred to as the sensitivity function, for assessing the sensitivity of the outpllts to small changes in the input at a given cycle of the statistical process. We give several examples from variolls areas in statistics illustrating the general applicability of the sensitivity fUl1ction and show how and where the sensitivity function fits into the statistical cycle. Some applicatiol1s of the sensitivity function lead to known statistical techniqlles. while other applications produce new ones

Flexural Behavior of RC One-Way Slabs Strengthened with Fiber Reinforcement Cementations Matrix, FRCM.

المحاكاة العددية التي أجريت في هذا البحث للتحقيق في سلوك الانحناء للسقوف الخرسانية احادية الاتجاه والمقواة بعجينة اسمنتية مسلحة بالالياف المركبة. تم إجراء تحليل العناصر المحددة ثلاثية الأبعاد باستخدام ANSYS (17.2). تتمثل القضايا الرئيسية التي يركز عليها هذا البحث في: (1) تأثير نوع الالياف المستخدمة في العجينة الاسمنتية على سلوك الانثناء للسقوف الخرسانية من ناحية الحمل الاقصى والهطول، (2) تأثير قيم مختلفة لمقاومة الانضغاط لخرسانة السقف و (3) تاثير عدد طبقات الالياف في العجينة الاسمنية. بينت النتائج ان نوع الالياف له تاثير واضح على سلوك الانثناء للسقوف المقواة. كما أظهرت الدراسة العديدية أن قوة الانثناء تزداد بزيادة مقاومة انضغاط الخرسانة عندما يكون الفشل محكومًا بسحق الخرسانة. بالإضافة إلى ذلك، كان زيادة عدد طبقات الالياف المركبة تأثير واضح على سلوك السقف الخرساني، ولكن الى عدد محدد لان بعد ذلك يكون الفشل محكوم بتصرف الخرسانة في منطقة الانضغاط.Numerical simulation performed in this paper to explore the flexural behavior of RC one way slab strengthened with fiber reinforcement cementations matrix (FRCM). Three dimensional finite element analysis was performed by using ANSYS (17.2). The main issues focused in this paper are (1) the effect of FRCM fabric types on the flexural behavior of strengthened RC slab in terms of both ultimate capacity and deflection, (2) effect of variables compressive strength value of the concrete slab and (3) number of fabric layers for composite material effect. The results showed that the fabric type had a clear effect on the flexural behavior of the strengthened slab. The parametric study also revealed that the flexural strength increases with increasing the compressive strength of concrete when the failure is represented by crushing of the concrete strut. In addition to, the number of fabric layers for composite material had a clear effect on the behavior of RC slab, but to a specified number because then the failure is determined by the action of the concrete in the compression zone

PELATIHAN DAN PENDAMPINGAN PEMBENTUKAN FORUM PENGURANGAN RESIKO BENCANA DI DESA PAIT, KEC. KASAMBON, KAB. MALANG

Indeks resiko bencana Kabupaten Malang pada tahun 2019 mempunyai skor 219 dengan kategori tinggi, terutama berkaitan dengan bencana banjir dan tanah longsor. Sebagai upaya penanggulangan bencana berbasis masyarakat maka dibentuklah Desa Tangguh Bencana. Objek dalam pengabdian ini adalah Desa Pait, Kecamatan Kesambon, Kabupaten Malang. Desa ini dipilih karena memiliki topografi yang unik dan sering mengalami bencana alam seperti banjir, tanah longsor, dan angin puting. Pengabdian ini bertujuan untuk inisiasi pembentukan kelembagaan bencana tingkat desa secara bottom up. Tahap awal yang dilakukan adalah pemahaman tentang konsep penanggulangan bencana, manajemen pengurangan resiko, perencanaan penanggulangan bencana dan pendampingan pembentukan Forum Pengurangan Resiko Bencana (FPRB) desa Pait. Selain itu, dibentuknya FPRB di Desa Pait adalah untuk meningkatkan partisipasi masyarakat dan responsifitas secara kelembagaan

Modeling Probabilistic Networks of Discrete and Continuous Variables

AbstractIn this paper we show how discrete and continuous variables can be combined using parametric conditional families of distributions and how the likelihood weighting method can be used for propagating uncertainty through the network in an efficient manner. To illustrate the method we use, as an example, the damage assessment of reinforced concrete structures of buildings and we formalize the steps to be followed when modeling probabilistic networks. We start with one set of conditional probabilities. Then, we examine this set for uniqueness, consistency, and parsimony. We also show that cycles can be removed because they lead to redundant probability information. This redundancy may cause inconsistency, hence the probabilities must be checked for consistency. This examination may require a reduction to an equivalent set instandard canonicalform from which one can always construct a Bayesian network, which is the most convenient model. We also perform a sensitivity analysis, which shows that the model is robust

Apparent Weekly and Daily Earthquake Periodicities in the Western United States

Analysis of apparent seismicity rate (ASR) using magnitude ≥1 earthquakes located in the western United States confirmed the existence of prominent spectral peaks with periods of 1 and 7 days. The number of recorded earthquakes on Sundays for the duration of 1963-2008 is about 5% higher than that on weekdays, and, more significantly, there is a 9% increase of ASR in the early morning compared with that in the middle of the days. Significant similarities in the spatial distributions of the weekly and daily variations suggest that the two types of variations have the same sources and both originate from periodic variations in cultural noise that lead to periodic variations in the detectability of the seismic networks. Comparisons with freeway traffic flow data suggest that traffic flow on the freeways is not the only significant factor in the observed periodicities. Instead, ambient noise from all the ground traffic, operating machineries, and building shaking is probably the major cause of the observed apparent periodicities. The observed temporal variations in ambient noise as reflected by the ASR can be used as objective guidelines for choosing the best time/day for noise-sensitive scientific experiments

An Enhanced Multi-Objective Biogeography-Based Optimization Algorithm for Automatic Detection of Overlapping Communities in a Social Network with Node Attributes

Community detection is one of the most important and interesting issues in social network analysis. In recent years, simultaneous considering of nodes' attributes and topological structures of social networks in the process of community detection has attracted the attentions of many scholars, and this consideration has been recently used in some community detection methods to increase their efficiencies and to enhance their performances in finding meaningful and relevant communities. But the problem is that most of these methods tend to find non-overlapping communities, while many real-world networks include communities that often overlap to some extent. In order to solve this problem, an evolutionary algorithm called MOBBO-OCD, which is based on multi-objective biogeography-based optimization (BBO), is proposed in this paper to automatically find overlapping communities in a social network with node attributes with synchronously considering the density of connections and the similarity of nodes' attributes in the network. In MOBBO-OCD, an extended locus-based adjacency representation called OLAR is introduced to encode and decode overlapping communities. Based on OLAR, a rank-based migration operator along with a novel two-phase mutation strategy and a new double-point crossover are used in the evolution process of MOBBO-OCD to effectively lead the population into the evolution path. In order to assess the performance of MOBBO-OCD, a new metric called alpha_SAEM is proposed in this paper, which is able to evaluate the goodness of both overlapping and non-overlapping partitions with considering the two aspects of node attributes and linkage structure. Quantitative evaluations reveal that MOBBO-OCD achieves favorable results which are quite superior to the results of 15 relevant community detection algorithms in the literature

Aspal Modifikasi Dengan Penambahan Plastik Low Liniear Density Poly Ethylene (LLDPE) Ditinjau Dari Karakteristik Masrhall Dan Uji Penetrasi Pada Lapisan Aspal Beton (AC-BC)

This reseach was conducted by reviewing the impact of the addution of plastic plastik low linear density poly ethylene (LLDPE) in a mixturu of AC-BC layer. Next, calculate the optimum bitumen content and continued with the manufacture of test specimens to determine the optimum levels af- ter the analysis process by perfoming the process measuring, weighing, and testing with marshall. From the results of analysis obtained value of the optimum bitumen content that meets the sixth requisite criteria for the mixture according to the specification of Bina Marga 2010 revision III. After that followed the variation with the addition of plastic low linear density poly ethylene (LLDPE) with levels of pesecnt 1%, 3%, 5%, 7%, 9% calculate on the weight of the asphalt. From the analysis of the test reselt, the velue of the stability of the increasing levels of LLDPE in in - creasing the value of stability. But in value VIM no specifications that meet the standarts of Bina Marga 2010 revision III. The Velues decreased penetration of asphalt mix