| 22401. |
- Khaksar, Mohsen, et al.
(författare)
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Monitoring safety properties of composite web services at runtime using CSP
- 2009
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Ingår i: 13th Enterprise Distributed Object Computing Conference Workshops, 2009. EDOCW 2009. - : IEEE. - 9781424455638 ; , s. 107-113
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Konferensbidrag (refereegranskat)abstract
- Nowadays, service oriented architecture has been given strong attention as an important approach to integrate heterogeneous systems, in which complex services are created by composing simplerservices offered by various systems. The correctness of composition requires techniques to verify if the composite service behaves properly. To this end, in this paper we propose a new method forruntime monitoring of composite services which uses Communicating Sequential Processes (CSP) to specify properties formally. Then, the CSP specification of properties is translated to a Labeled Transition System (LTS). In order to verify the safety of a composite service, we traverse the generated LTS at runtime. Existing methods almost use temporal logic to specify safety properties. There are two advantages in using CSP: 1) similarity of CSP operators and service composition patterns makes CSPstraightforward to be used by users. 2) there are some properties which can not be specified by temporal logic, while they can be expressed using CSP.
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| 22402. |
- Khalaf, Ghadban, et al.
(författare)
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A Tobit Ridge Regression Estimator
- 2014
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Ingår i: Communications in Statistics - Theory and Methods. - : Informa UK Limited. - 0361-0926 .- 1532-415X. ; 43:1, s. 131-140
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Tidskriftsartikel (refereegranskat)abstract
- This article analyzes the effects of multicollienarity on the maximum likelihood (ML) estimator for the Tobit regression model. Furthermore, a ridge regression (RR) estimator is proposed since the mean squared error (MSE) of ML becomes inflated when the regressors are collinear. To investigate the performance of the traditional ML and the RR approaches we use Monte Carlo simulations where the MSE is used as performance criteria. The simulated results indicate that the RR approach should always be preferred to the ML estimation method.
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| 22403. |
- Khalaf, Ghadban, et al.
(författare)
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Modified Ridge Regression Estimators
- 2013
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Ingår i: Communications in Statistics - Theory and Methods. - : Informa UK Limited. - 0361-0926 .- 1532-415X. ; 42:8, s. 1476-1487
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Tidskriftsartikel (refereegranskat)abstract
- Ridge Regression is a variant of ordinary multiple linear regression whose goal is to circumvent the problem of predictors collinearity. It gives-up the Ordinary Least Squares (OLS) estimator as a method for estimating the parameters of the multiple linear regression model . Different methods of specifying the ridge parameter k were proposed and evaluated in terms of Mean Square Error (MSE) by simulation techniques. Comparison is made with other ridge-type estimators evaluated elsewhere. The new estimators of the ridge parameters are shown to have very good MSE properties compared with the other estimators of the ridge parameter and the OLS estimator. Based on our results from the simulation study we may recommend the new ridge parameters to practitioners.
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| 22404. |
- Khalid, Hamza, et al.
(författare)
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Substituting Ti-64 with Aa2099 as material of a commercial aircraft pylon
- 2021
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Ingår i: Advances in Materials Science. - : Sciendo. - 2083-4799. ; 21:2, s. 77-92, s. 28-28
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Tidskriftsartikel (refereegranskat)abstract
- The aircraft industry is striving to reduce the weight of aircraft to save fuel and hence reduce total cost. New alloys and composites with properties such as low weight and high strength are continuously developed. Titanium alloys have the best strength-to-weight ratio among metals which makes them very suitable for aircraft applications. Ti-64 is the most common Titanium alloy used in aircraft. AA2099 is a 3rd generation Al-Li alloy and has the lowest density among all Aluminium alloys making it very attractive for aircraft applications. Pylons of commercial aircraft are currently made primarily with Ti-64 and this study focused on the replacement of Ti-64 with AA2099. Loading conditions, operating temperature, corrosion resistance, manufacturability and recyclability of the pylon were analysed of both Ti-64 and AA2099. Three critical scenarios were chosen for the loading conditions of the pylon. These were simulated using finite element analysis first using Ti-64 and then AA2099. From the results, it is evident that using AA2099 as the material of the pylon instead of Ti-64 offered weight savings. The operating temperature, manufacturability and recyclability also showed advantages when using AA2099 whereas corrosion factors favoured Ti-64, since AA2099 was found to be very prone to galvanic corrosion.
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| 22405. |
- Khalid, Saba, et al.
(författare)
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An integrated perspective of social exchange theory and transaction cost approach on the antecedents of trust in international joint ventures
- 2017
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Ingår i: International Business Review. - : Elsevier. - 0969-5931 .- 1873-6149. ; 26:3, s. 491-501
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates the antecedents of trust in International Joint Ventures (IJVs). Building on social exchange theory (SET) and transaction cost theory (TCT), we develop an integrated framework in which trust development requires two sets of antecedents: (1) social antecedents (prior alliance experience with partner, partner’s cultural sensitivity and reputation, inter-partner communication, expected longevity of the IJVs), and (2) structural antecedents (interdependence, ownership share, resource complementary). The developed framework is tested using web-survey data collected from 89 IJVs established by Nordic firms in Asia, Europe and America. Empirical data analysis based on structural equation modelling suggests that a partner’s cultural sensitivity and reputation, inter-partner communication, and expected longevity are the social antecedents from SET that enhance trust. From TCA, the structural antecedent of resource complementary develops trust, while balanced interdepen- dence and balanced ownership are unrelated to trust. These findings have important implications for managers planning to form and manage IJVs.
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| 22406. |
- Khalili, Farhad, et al.
(författare)
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Bara 13 procent slutför sin chatt-KBT – forskaren: Snabb hjälp lockar
- 2023
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Annan publikation (ljud/tal) (populärvet., debatt m.m.)abstract
- Av 12 000 personer som laddade ned appen Mendly var det bara 13 procent som fullföljde sin KBT-behandling. Det visar en studie från Linnéuniversitetet om chatterapiföretaget Mendly, som erbjudit KBT-behandling för personer med ångest och depressioner. "De patienter som lägger mer tid, kraft och och fullföljer, de får bättre utfall", säger Cecilia Dautovic, forskare och lektor.
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| 22407. |
- Khalili, Nastaran, et al.
(författare)
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Circular economy in wood multi-storey building construction : A systematic literature review
- 2023
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Ingår i: Proceedings of the International Conference “Sustainable Built Environment and Urban Transition”. - : Linnaeus University Press. - 9789180820424
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Konferensbidrag (refereegranskat)abstract
- There has been a growing interest in wood-based buildings in Europe in recent years. A reason for this is that sustainability issues are becoming increasingly important in the building and construction sector, which is responsible for around 40% of the total CO2 emissions and between 25-30% of the total waste discarded in landfills, worldwide. Previous studies have shown that linear economic practices regarding used wood in construction and discarding it with minimal reuse or recycling after the demolition of the building results in significant environmental impacts. Therefore, applying circular economy concepts and criteria in wood building construction seems vital. This article provides state-of-the-art literature review of circular economy and its implementation in wood multi-storey building construction. A systematic literature review is conducted in which relevant peer reviewed articles were retrieved and explored to identify the state-of-the-art and current knowledge gaps that require further research. From an initial set of 157 scientific papers, a set of 15 highly relevant papers were selected for in-depth examination. The visualization tool VOSViewer is used to identify and gather the relevant data and information from the following academic databases: Web of science, ScienceDirect and Google Scholar. This systematic review provides concepts, indicators and tools for circular economy and circular construction solutions for multi-storey wood building construction. It also highlights the key knowledge gaps that require further research. By addressing these issues, this study aims to contribute to promoting circularity in design, construction, use, and post-use phases of wood multi-storey buildings, which are urgently needed in the construction sector to mitigate climate change.
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| 22408. |
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| 22409. |
- Khamitova, Raisa
(författare)
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Symmetries and conservation laws
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Conservation laws play an important role in science. The aim of this thesis is to provide an overview and develop new methods for constructing conservation laws using Lie group theory. The derivation of conservation laws for invariant variational problems is based on Noether’s theorem. It is shown that the use of Lie-Bäcklund transformation groups allows one to reduce the number of basic conserved quantities for differential equations obtained by Noether’s theorem and construct a basis of conservation laws. Several examples on constructing a basis for some well-known equations are provided.Moreover, this approach allows one to obtain new conservation laws even for equations without Lagrangians. A formal Lagrangian can be introduced and used for computing nonlocal conservation laws. For self-adjoint or quasi-self-adjoint equations nonlocal conservation laws can be transformed into local conservation laws.One of the fields of applications of this approach is electromagnetic theory, namely, nonlocal conservation laws are obtained for the generalized Maxwell-Dirac equations. The theory is also applied to the nonlinear magma equation and its nonlocal conservation laws are computed.
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| 22410. |
- Khan, A., et al.
(författare)
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A comprehensive review of the methane decomposition using a gliding arc discharge reactor for hydrogen generation
- 2023
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Ingår i: Journal of the Energy Institute. - : Elsevier. - 1743-9671 .- 1746-0220. ; 109
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Tidskriftsartikel (refereegranskat)abstract
- The use of fossil fuels has caused an ongoing increase in greenhouse gases (GHGs), which have a negative impact on both the environment and human health. The world requires an alternative green sustainable fuel that can solve these problems. Hydrogen (H2) can be considered as an alternative green energy source as it has zero carbon emissions. Methane (CH4) decomposition is a potential technique to produce H2 fuel. Gliding arc discharge (GAD) reactors have gained significant attention to produce H2 from the decomposition of CH4. This review focuses on the application of GAD reactors for CH4 conversion. The effects of different parameters, such as operation conditions, additives, geometric configuration, and catalysts, on the performance of the GAD reactor, are discussed in this review. © 2023 Energy Institute
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