Wyniki wyszukiwania - BazTech

1

Throughput, Spectral, and Energy Efficiency of 5G Massive MIMO Applications Using Different Linear Precoding Schemes

Salah Ibrahim, Rahouma Kamel Hussein, Hussein Aziza I., Mabrook M. Mourad

International Journal of Electronics and Telecommunications

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2023

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Vol. 69, No. 1

185--191

EN

On fifth-generation wireless networks, a potential massive MIMO system is used to meet the ever-increasing request for high-traffic data rates, high-resolution streaming media, and cognitive communication. In order to boost the trade-off between energy efficiency (EE), spectral efficiency (SE), and throughput in wireless 5G networks, massive MIMO systems are essential. This paper proposes a strategy for EE 5G optimization utilizing massive MIMO technology. The massive MIMO system architecture would enhance the trade-off between throughput and EE at the optimum number of working antennas. Moreover, the EE-SE tradeoff is adjusted for downlink and uplink massive MIMO systems employing linear precoding techniques such as Multiple -Minimum Mean Square Error (M-MMSE), Regularized Zero Forcing (RZF), Zero Forcing (ZF), and Maximum Ratio (MR). Throughput is increased by adding more antennas at the optimum EE, according to the analysis of simulation findings. Next, utilizing M MMSE instead of RZF and ZF, the suggested trading strategy is enhanced and optimized. The results indicate that M-MMSE provides the best tradeoff between EE and throughput at the determined optimal ratio between active antennas and active users equipment’s (UE).

2

An adaptive method based on PC-Kriging for system reliability analysis of truss structures

Chen Pengyu, Zhao Cunbao, Yao He, Zhao Shengnan

Eksploatacja i Niezawodność

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2023

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Vol. 25, no. 3

art. no. 169497

EN

In practice, a truss consists of a large number of members which makes it a complex system. This leads to difficulties to estimate the system reliability due to computational costs. An adaptive method is thereby proposed to deal with this issue. It constructs a global metamodel to quickly estimate the rough reliability index of a truss. According to the estimated reliability index, the differential evolution algorithm is performed to generate more samples located in an expanded domain so that more representative failure modes can be identified. Combined with AK-SYSi, local metamodels of representative failure mods are built, and updated through active learning. When the convergence criterion is satisfied, the results of system reliability analysis can be obtained. Eventually, two examples of truss structures are studied to illustrate the superiority of the proposed method in balancing accuracy and efficiency. The results indicate that the proposed method makes a good balance between accuracy and efficiency when it is applied to analyze the system reliability of the truss.

3

Economics of flotation plant against different size reduction alternatives and flotation grades

Tuzcu E. Tuğcan, Demirtaş Zafer

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 5

art. no. 154813

EN

This paper quantitatively shows the effect of run-of-mine (ROM) feed grade on flotation plant capacity, and also the combined effects of different feed grades and the size reduction alternative combinations on the project economics. Project economics are defined as CAPEX and OPEX The project profitability was estimated based on a “Cash Flow Model” along the life of the mine, which is ten years. The parameter for tracking project return or profitability is called NPV and IRR (internal rate of return), respectively. These parameters are standard parameters for control of project return in all engineering studies. In the scope of the study, there are a series of case studies including three different comminution alternatives in combination with three different ROM feed grade alternatives. Therefore, the nine case studies were compared based on economics which resulted from different equipment combinations and as well as the different types/amounts of process consumables. Among all the cases, Case 1 (Conventional circuit with 0.1% feed grade) gave the lowest CAPEX whereas Case 9 (High Pressure Grinding Rolls_HPGR circuit with 0.3% feed grade) gave the highest CAPEX. OPEX wise, Case 7 (HPGR circuit with 0.1% feed grade) produced the lowest whereas Case 6 (Semi-Autogenous Ball mill Crusher_SABC circuit with 0.3% feed grade) gave the highest value of OPEX. The NPV of the HPGR circuit with 0.3% feed grade case was found as maximum, which showed the quantitative effect of feed grade and equipment combination on flotation plant economics.

4

Elastic full waveform inversion based on equivalent staggered grid FDM and inter-parameter trade-off mitigation

Li Qingyang, Wu Guochen

Acta Geophysica

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2022

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Vol. 70, no 6

2555--2579

EN

Elastic full waveform inversion (EFWI) has increasingly been applied in seismic exploration as computer performance improves. EFWI significantly improves calculation efficiency, but requires very large computer storage space and suffers interparameter trade-off and local minima problems. Preconditioning the gradients based on elastic wave mode decomposition can effectively mitigate inter-parameter trade-offs, but the decomposition-based scheme may further increase the memory usage, which limits EFWI application. The equivalent staggered grid (ESG) scheme in acoustic medium requires less memory usage and generates results numerically equivalent to those using the standard staggered grid (SSG) scheme. In this paper, we extend the ESG scheme to second-order elastic wave equations in terms of velocity, producing results numerically equivalent to the SSG ones based on first-order velocity–stress wave equations while reducing memory usage by 45% compared with the SSG scheme. We then apply the ESG scheme to EFWI and derive the formula of the preconditioned gradient of the S-wave velocity. Finally, three numerical examples demonstrate that applying the ESG scheme to decomposition-based EFWI can significantly reduce computer memory usage and mitigate the trade-offs between the P- and S-wave velocities.

5

Evaluation of the efficiency of the production changeover process using the simulation method

Milewski Dariusz

Gospodarka Materiałowa i Logistyka

|

2021

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nr 7

2--12

EN

The paper presents the problem of the optimization of the length of the series and production batch, and thus the optimal frequency of production changeovers, taking into account the total cost approach and the use of the simulation method. The author has developed a model which, with the given parameters (costs and time of production changeover, costs of maintaining stocks of finished products and storage, value of manufactured products, sales variability and predictability), allows to calculate the economic effects of determining the length of a series and a production batch. In the author's opinion, the simulation method (at least in some cases) may be more appropriate in solving the problem of determining the optimal length of a series or production batch than the use of mathematical formulas. The calculations also took into account the impact of series and batch optimization on the company's profitability in order to assess the significance of this problem for financial results. The calculations were performed for two sample products and for two probability distributions — Gauss and Gamma. The results of the research show that the optimization of the production series may be important from the point of view of economic efficiency, that mathematical formulas may be less suitable for calculating the optimal production series than computer simulation, and that, in the case of significant variability of the sales level, in addition to the costs of changing production and maintaining inventories, lost sales costs should also be taken into account.

PL

W artykule przedstawiono problematykę optymalizacji długości serii i partii produkcyjnej, a więc i optymalnej częstotliwości przezbrojenia produkcji przy uwzględnieniu podejścia całkowitokosztowego i zastosowaniu metody symulacji. Autor opracował model, który przy zadanych parametrach (koszty i czas przestawienia produkcji, koszty utrzymania zapasów wyrobów gotowych i magazynowania, wartość produkowanych wyrobów, zmienność i przewidywalność sprzedaży) pozwala na obliczenie skutków ekonomicznych ustalenia długości serii i partii produkcyjnej. W opinii autora metoda symulacji (przynajmniej w niektórych przypadkach) w rozwiązywaniu problemu ustalenia optymalnej długości serii lub partii produkcyjnej może być właściwsza niż zastosowanie formuł matematycznych. W obliczeniach uwzględniono również wpływ optymalizacji serii i partii produkcyjnej na rentowność przedsiębiorstwa, aby ocenić istotność tego problemu dla wyników finansowych. Obliczenia zostały przeprowadzone dla dwóch przykładowych produktów i dla dwóch rozkładów prawdopodobieństwa — Gaussa i Gamma. Wyniki badań wskazują, że optymalizacja serii produkcyjnej może mieć istotne znaczenie z punktu widzenia efektywności ekonomicznej, że formuły matematyczne mogą być mniej odpowiednie do obliczania optymalnej serii produkcyjnej niż symulacja komputerowa oraz że w przypadku występowania znaczącej zmienności poziomu sprzedaży, oprócz kosztów przestawienia produkcji i utrzymania zapasów, powinno się uwzględniać także koszty utraconej sprzedaży.

6

The Tradeoff between Growth and Environment: Evidence from China and the United States

Xu Jing, Li Jianjun

Problemy Ekorozwoju

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2018

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Vol. 13, nr 1

15--20

EN

This paper empirically analyzes individual attitudes on the tradeoff between environment and economy, and factors that might influence such choice for two representative countries: China and the United States. Based on the World Value Survey, the Chinese are found more inclined to support environmental protection, while people from the United States choose economic growth as priority. Considering three sets of correlates of sociodemo-graphics, environmental attitude and social context, variables such as education, political affiliation and envi-ronmental consciousness show significance in influencing personal preferences, and the effect of health, age, employment and marital status demonstrates heterogeneity across countries. Such micro-level evidence on how the public weighs the economy versus environment can provide policy guidance for the government to better respond to public opinions.

PL

Artykuł poddaje analizie indywidualne postawy odnoszące się do kompromisu pomiędzy środowiskiem a eko-nomią, a także czynniki, które mają wpływ na kształtowanie się takich postaw, w odniesieniu do dwóch ważnych krajów: Chin i USA. Według danych World Value Survey okazuje się, ze Chińczycy są bardziej skłonni wspierać ochronę środowiska, podczas gdy Amerykanie za priorytet uznają rozwój ekonomiczny. Uwzględniając trzy zbiory korelatów odnoszące się do socjodemografii, postaw wobec środowiska i kontekstu społecznego, zmienne takie jak edukacja, orientacja polityczna i świadomość ekologiczna, okazuje się, że te czynniki odgrywają istotne znaczenie w kształtowaniu indywidualnych priorytetów, a kwestie zdrowia, wieku, zatrudnienia i stanu cywilnego wypadają podobnie w różnych krajach. Dane z takiego mikro poziomu pokazują, jak ludzie indywidualnie rozstrzygają spór pomiędzy ekonomią a środowiskiem, co stanowi polityczną wskazówkę dla rządu, dzięki której można lepiej odpowiadać na nastroje społeczne.

7

Capital structure determinants and firms’ performance : empirical evidence from Thailand, Indonesia and Malaysia

Mursalim, Mallisa M., Kusuma H.

Polish Journal of Management Studies

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2017

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Vol. 16, No. 1

154--164

EN

Financing decision of the firms can be a difficult decision in corporate finance. Many factors may affect these decisions. These choices may also influence capital structure and can improve firm performance. The objective of this study is to investigate the capital structure determinants of the firms in Indonesia, Malaysia, and Thailand. In this study, the investigated variables are profitability, firm size, growth opportunity, volatility, gross domestic product (GDP rate), inflation rate, and corporate governance. Using path analysis of two-multiple regressions, the leverage behavior is examined for the firm samples consisting of 94 Indonesian firms, 153 Malaysian firms, and 74 Thailand firms for the period 2008-2012. The results show that company’s profitability, firm size and volatility have dominant and consistent roles in explaining the variation of the capital structure. The variables of growth opportunity, gross domestic product, inflation rate and corporate governance in general influence the variation of the capital structure. Furthermore, the capital structure of firms was significantly related to the firm performance.

PL

Decyzja dotycząca finansowania firm może być trudną kwestią w zakresie finansów korporacyjnych. Na takie decyzje może wpływać wiele czynników. Dokonywane wybory mogą również wpływać na strukturę kapitału i mogą poprawić wydajność firmy. Celem tego badania jest zbadanie determinant struktury kapitałowej firm w Indonezji, Malezji i Tajlandii. W badaniu tym badane zmienne to: rentowność, wielkość firmy, możliwości wzrostu, zmienność, produkt krajowy brutto (stopa PKB), stopa inflacji i ład korporacyjny. Wykorzystując analizę ścieżek regresji, zachowanie dźwigni zbadano na podstawie firmowych próbek składających się z 94 indonezyjskich, 153 malezyjskich i 74 tajlandzkich firm w latach 2008-2012. Wyniki pokazują, że rentowność, wielkość i zmienność firmy pełnią dominujące i stałe role w wyjaśnianiu zmienności struktury kapitału. Zmienne dotyczące możliwości wzrostu, produktu krajowego brutto, stopy inflacji i ładu korporacyjnego, wpływają na zmienność struktury kapitału. Ponadto struktura kapitałowa firm była istotnie powiązana z wynikami firmy.

8

Integrating mitigation and adaptation in climate, water and development policies in Krakow

Dubel A.

Ekonomia i Środowisko

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2017

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nr 1

226--235

EN

In view of such a complex phenomena as climate change not sufficient outcomes emerge from concentrating separately on mitigation or adaptation efforts, but rather it is their integration in a coherent policy and the subsequently planned actions that could increase effectiveness and efficiency as well as intensify the desired results. This working hypothesis is elaborated in the paper based on the case study of the city of Krakow in the Southern Poland. The aim of the paper is to identify the synergies and trade-offs from the climate mitigation and adaptation efforts planned within the climate, water and development sectors in Krakow. The scoping study of the policies and strategic documents was performed with that respect and the state-of-the-art literature was studied to capture the latest advancements in the climate mitigation and adaptation integration studies in order to develop the research method. The applied method was validated as relevant for integration of these aspects with the focus on the cities. The results show the landscape of the planned strategic actions towards mitigation and adaptation to climate change as well as synergies and trade-offs between the two. In the discussion the results are analysed in view of the identified performed studies of this type.

9

Target effect on the kinematics of Taekwondo Roundhouse Kick – is the presence of a physical target a stimulus, influencing muscle-power generation?

Wąsik J., Shan G.

Acta of Bioengineering and Biomechanics

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2015

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Vol. 17, no. 4

115--120

EN

Taekwondo is famous for its powerful kicking techniques and the roundhouse kick is the most frequently used one. In earlier literature, the influence of a physical target (exiting or not) on kicking power generation has not been given much attention. Therefore, the aim of this study was to investigate the kinematics of roundhouse kick execution and its factors related to power generation. 6 ITF taekwondo practitioners voluntarily participated in this study. They were asked to perform kicks with and without a physical target. The first kick aimed at breaking a board while the second one was a kick into the air. A Smart-D motion capture system (BTS S.p.A., Italy) was used to quantitatively determine their kinematic characteristics during each kick. The main findings showed that kicks aiming at a breaking board were significantly slower than kicks without a physical target (maximal kick-foot velocities were 10.61 ± 0.86 m/s and 14.61 ± 0.67 m/s, respectively, p < 0.01), but the kicking time of the former was shorter (0.58 ± 0.01 s and 0.67 ± 0.01, respectively, p < 0.01). The results suggest that a physical target will negatively influence the kick-foot velocity, which is not necessarily a disadvantage for creating a high quality kick. Possible motor control mechanisms are discussed for the phenomenon. The study made it clear: trainings with and without physical targets would develop different motor control patterns. More studies are needed for identifying the effectiveness of different controls and efficiencies of their training.

10

Isometric scaling relationship between leaf number and size within current-year shoots of woody species across contrasting habitats

Li T., Deng J., Wang G., Cheng D., Yu Z.

Polish Journal of Ecology

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2009

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Vol. 57, nr 4

659-667

EN

The scaling relationship between the number and size of plant.s components has been observed traditionally as reflective of a trade-off in resource allocation over ontogeny. The recent finding of a negative isometric leaf size/number trade-off across 24 deciduous woody species extends knowledge of such trade-offs to current-year shoots. Before generally accepted, this isometry has to be consistent across more datasets that represent diverse habitats. We tested this scaling relationship using 12 deciduous shrub species from the western Gobi Desert and 56 woody species from the northeastern temperate zone of China. Our results showed that leaf number per stem mass of current-year shoots scaled approximately isometrically with individual leaf mass within and across habitats, which, combined with the independence of total leaf mass and individual leaf mass, supports isometric scaling for shoot-scale leaf deployment. However, the intercepts of these relationships decreased significantly along the environmental gradients, suggesting that habitats could place a constraint on the total leaf number that can be supported by a given size shoot. Convergence towards higher leaf number and smaller leaf size for some desert species suggests important adaptive implications for photosynthetic carbon gain and reproductive growth.

11

Jednopoziomowe i wielopoziomowe relacje trade-off w przedsiębiorstwie : wybrane aspekty

Milewska B.

Zeszyty Naukowe. Problemy Transportu i Logistyki / Uniwersytet Szczeciński

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2007

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Nr 6

49--58

PL

[...]W artykule zaproponowany został podział relacji trade-off na relacje jednopoziomowe typu pierwszego, drugiego i trzeciego oraz wielopoziomowe. Przedstawiono przykłady występowania tych relacji w przedsiębiorstwach oraz wskazano na możliwość wystąpienia w relacjach wielopoziomych współzależności trade-up, w której poprawie ulegają co najmniej dwa, zwykle przeciwstawne elementy, takie jak koszty i jakość produktu bądź obsługi.[...]

EN

In the paper the division into trade-off relations of one (type I, II and III) and multiply levels has been proposed. The examples of the appearing in the enterprises have been presented and possibility of the appearing in the relations of multiply levels the trade-off correlations has been indicated in which relations at least two usually opposite elements such costs and quality of a product or service are improved.

12

Możliwości zastąpienia relacji trade-off relacją trade-up w logistyce i produkcji (cz. 2)

Milewska B.

Logistyka

|

2006

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nr 1

24-25

13

A generalization of the Zionts-Wallenius multiple criteria decision making algorithm

Kaliszewski I., Zionts S.

Control and Cybernetics

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2004

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Vol. 33, no 3

477-500

EN

In multicriteria problem solving, much can be learned by observing the decision-making process. Some, if not many, of the theoretical constructs used in some academically-generated models are simply not necessary. Taking this into account, we generalize the Zionts-Wallenius Multiple Criteria Decision Making Algorithm. We generalize the approach so that it can solve general convex problems. We do this by drawing from other methods, and by incorporating what we have learned in our work. To deal with the class of convex problems we face, we broaden the concept of tradeoff, and use global tradeoffs. Theory is developed, and then a method incorporating the theory is presented. A small example is included. We discuss how our development enriches decision-making tools currently available. We discuss applications in finance and technology.