Viser treff 533-552 av 914

    • N-list-enhanced heuristic for distributed three-stage assembly permutation flow shop scheduling 

      Ying, Kuo-Ching; Pourhejazy, Pourya; Fu, Po-Jiu (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-07-04)
      System-wide optimization of distributed manufacturing operations enables process improvement beyond the standalone and individual optimality norms. This study addresses the production planning of a distributed manufacturing system consisting of three stages: production of parts (subcomponents), assembly of components in Original Equipment Manufacturer (OEM) factories, and final assembly of products ...
    • Når blir skipsfarten grønn? 

      Hoff, Bjarte; Østrem, Trond (Kronikk; Chronicle, 2018-04-25)
      n av utfordringene i forbindelse med dagens skipsfart er utslipp til luft, hovedsakelig karbondioksid og nitrogenoksider. Disse utslippene er knyttet til oljefyrte forbrenningsmotorer som dominerer dagens skipsflåte. Det er overveiende sannsynlig at det er en direkte sammenheng mellom global oppvarming og utslipp av klimagasser. Utslipp til luft kan også bidra til sur nedbør og svevestøv, for å nevne ...
    • A New Development of the Classical Single Ladder Problem via Converting the Ladder to a Staircase 

      Høibakk, Ralph; Lukkassen, Dag; Meidell, Annette; Persson, Lars Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-08)
      Our purpose is to shed some new light on problems arising from a study of the classical Single Ladder Problem (SLP). The basic idea is to convert the SLP to a corresponding Single Staircase Problem. The main result (Theorem 1) shows that this idea works fine and new results can be obtained by just calculating rational solutions of an algebraic equation. Some examples of such concrete calculations ...
    • A new discrete Hardy-type inequality with kernels and monotone functions 

      Kalybay, Aigerim; Persson, Lars Erik; Temirkhanova, Ainur (Peer reviewed; Journal article; Tidsskriftartikkel, 2015-10-06)
      A new discrete Hardy-type inequality with kernels and monotone functions is proved for the case 1<q<p<∞1<q<p<∞. This result is discussed in a general framework and some applications related to Hölder’s summation method are pointed out.
    • A new dispatching mechanism for parallel-machine scheduling with different efficiencies and sequence-dependent setup times 

      Wu, Gen-Han; Pourhejazy, Pourya; Li, Wang-Xian; Wu, Tai-Hsi (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-02-22)
      he Apparent Tardiness Cost (ATC) dispatching rule was initially developed to minimize tardiness in single machine scheduling problems. ATC extensions have been frequently applied in other production settings, relying heavily on blocking idle machine capacity with a single-machine outlook; this approach may not result in the best outcomes, considering that machines have different efficiencies. This ...
    • New dose-response model and SARS-CoV-2 quanta emission rates for calculating the long-range airborne infection risk 

      Aganovic, Amar; Cao, Guangyu; Wargocki, Pawel; Kurnitski, Jarek (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-12-14)
      Predictive models for airborne infection risk have been extensively used during the pandemic, but there is yet still no consensus on a common approach, which may create misinterpretation of results among public health experts and engineers designing building ventilation. In this study we applied the latest data on viral load, aerosol droplet sizes and removal mechanisms to improve the Wells Riley ...
    • A NEW GENERALIZATION OF BOAS THEOREM FOR SOME LORENTZ SPACES Λq(ω) 

      Kopezhanova, Aigerim; Nursultanov, Erlan; Persson, Lars Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2018)
      Let Λq( ω ), q > 0, denote the Lorentz space equipped with the (quasi) norm [<i>MATHEMATICAL FORMULA</I>] for a function f on [0,1] and with ω positive and equipped with some additional growth properties. A generalization of Boas theorem in the form of a two-sided inequality is obtained in the case of both general regular system [<i>MATHEMATICAL FORMULA</I>] and generalized Lorentz Λq( ω ) spaces
    • A new look at classical inequalities involving Banach lattice norms 

      Nikolova, Ludmila; Persson, Lars Erik; Varosanec, Sanja (Journal article; Peer reviewed; Tidsskriftartikkel, 2017-12-08)
      Some classical inequalities are known also in a more general form of Banach lattice norms and/or in continuous forms (i.e., for ‘continuous’ many functions are involved instead of finite many as in the classical situation). The main aim of this paper is to initiate a more consequent study of classical inequalities in this more general frame. We already here contribute by discussing some results of ...
    • A New Look at the Single Ladder Problem (SLP) via Integer Parametric Solutions to the Corresponding Quartic Equation 

      Høibakk, Ralph; Lukkassen, Dag; Meidell, Annette; Persson, Lars Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-18)
      The aim is to put new light on the single ladder problem (SLP). Some new methods for finding complete integer solutions to the corresponding quartic equation z 4 −2L z 3 +( L 2 − a 2 − b 2 ) z 2 +2L a 2 z− L 2 a 2 =0 z4−2Lz3+(L2−a2−b2)z2+2La2z−L2a2=0 are developed. For the case L≥ L min L≥Lmin , these methods imply a complete parametric representation for integer ...
    • New Practical Exercise in Lean Six Sigma for Masters Students in UiT – The Arctic University of Norway 

      Maharjan, Sujan (Master thesis; Mastergradsoppgave, 2019-06-28)
      Lean Six Sigma has proven to be a valuable tool for improving flow and quality in any business activities. It is being implemented by almost all business forms globally. It is now an important curriculum for engineering and management students. UiT- The Arctic University of Norway, Narvik is one of the fine institutions which provide training course on Lean Six Sigma for Master’s students studying ...
    • A New Two-Stage Stochastic Model for Reverse Logistics Network Design under Government Subsidy and Low-Carbon Emission Requirement 

      Yu, Hao; Solvang, Wei Deng (Konferansebidrag; Conference object, 2018-02-12)
      Nowadays, increasing number of companies incorporates the reverse logistics decisions into their supply chain design in order to cope with the enforced international and national legislation and improve the resource efficiency and public image. This paper investigates a new stochastic optimization model for designing a single-period multiproduct multi-level reverse logistics system under government ...
    • Non-directional Overcurrent Protection Relay Testing Using Virtual Hardware-in-the-Loop Device 

      Pham, Le Nam Hai; Wagle, Raju; Gonzalez-Longatt, Francisco; Acosta Montalvo, Martha Nohemi (Chapter; Bokkapittel, 2023-05-17)
      Protective relays are an integral part of the power grid, making it reliable and secure against abnormal conditions. Hardware-in-the-Loop (HIL) can be employed to test and validate digital protective relay devices in the real-time simulation comprising hardware and software before actual implementation. However, the HIL technique requires a complex and high-cost technical environment consisting of ...
    • Non-parametric Linear Technique for Measuring the Efficiency of Winter Road Maintenance in the Arctic Area 

      Hatamzad, Mahshid; Polanco Pinerez, Geanette (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-10-05)
      Improving the performance of Winter Road Maintenance (WRM) can increase the traffic safety and reduce the cost as well as environmental impacts. This study evaluates the efficiency of WRM technique, named salting, in the Arctic area by using Data Envelopment Analysis (DEA), which is a non-parametric linear method to measure the efficiencies of decision-making units (DMUs) based on handling multiple ...
    • Norwegian freshmen engineering students' self-efficacy, motivation, and view of mathematics in light of task performance 

      Rensaa, Ragnhild Johanne; Tossavainen, Timo (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-02-15)
      We report on 71 Norwegian freshmen engineering students' self-efficacy and motivation in mathematics. Students' responses to five-point Likert scales were analysed across three groups corresponding to different performance levels on a set of mathematical tasks. The groups were investigated to trace differences in self-efficacy, motivation, and the epistemological beliefs about the nature of mathematics. ...
    • Norwegian, Swedish, and Finnish first-year engineering students' motivational values and beliefs about the nature of mathematics 

      Tossavainen, Timo; Rensaa, Ragnhild Johanne; Haukkanen, Pentti (Chapter; Bokkapittel, 2022)
      We report from a Nordic research project that has investigated first-year engineering students in Norway, Sweden, and Finland, and the relationships between their task performance, motivational values, and beliefs about the nature of mathematics. The present paper focuses on the covariance between their motivational values and beliefs from the perspectives of gender and nationality. The results ...
    • A note about frequencies being close or amplitudes being small in frequency analysis 

      Rensaa, Ragnhild Johanne (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-10-10)
      In an earlier paper, an alternative method for how to solve the frequency analysis problem was offered. The object of the present paper is to bring about how to handle situations where the frequencies are close to each other or there is an amplitude that is really small.
    • A note on contributions concerning nonseparable spaces with respect to signal processing within Bayesian frameworks 

      Samko, Natasha Gabatsuyevna; Singh, Harpal (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-07-17)
      In this paper, we discuss the study of some signal processing problems within Bayesian frameworks and semigroups theory, in the case where the Banach space under consideration may be nonseparable. For applications, the suggested approach may be of interest in situations where approximation in the norm of the space is not possible. We describe the idea for the case of the abstract Cauchy problem ...
    • A note on the best constants in some hardy inequalities 

      Persson, Lars Erik; Samko, Stefan (Journal article; Tidsskriftartikkel; Peer reviewed, 2015)
      Abstract. The sharp constants in Hardy type inequalities are known only in a few cases. In this paper we discuss some situations when such sharp constants are known, but also some new sharp constants are derived both in one-dimensional and multi-dimensional cases.
    • A note on the maximal operators of Vilenkin-Nörlund means with non-increasing coefficients 

      Memić, Nacima; Persson, Lars Erik; Tephnadze, George; Kroo, A (Peer reviewed; Journal article; Tidsskriftsartikkel, 2016)
      In [14] we investigated some Vilenkin—Nörlund means with non-increasing coefficients. In particular, it was proved that under some special conditions the maximal operators of such summabily methods are bounded from the Hardy space H1/(1+α) to the space weak-L1/(1+α), (0 < α ≦ 1). In this paper we construct a martingale in the space H1/(1+α), which satisfies the conditions considered in [14], and so ...
    • A Novel Technique to Mitigate the Overlap-Time Effect in Current Source Inverters 

      Sohail, Umer; Østrem, Trond; Hoff, Bjarte (Chapter; Bokkapittel, 2023-08-31)
      Generally, the current source inverter is considered more reliable than the voltage source inverter due to the presence of inductor as an energy storage element on the DC link, but a disruption in the inductor current could significantly risk its reliability. To guarantee the reliable operation of current source inverter, an overlap time must be added to the gate signals of its switches. This ensures ...