Filtry
wszystkich: 756
wybranych: 634
-
Katalog
- Publikacje 634 wyników po odfiltrowaniu
- Czasopisma 1 wyników po odfiltrowaniu
- Osoby 16 wyników po odfiltrowaniu
- Wynalazki 4 wyników po odfiltrowaniu
- Projekty 7 wyników po odfiltrowaniu
- Kursy Online 30 wyników po odfiltrowaniu
- Wydarzenia 1 wyników po odfiltrowaniu
- Dane Badawcze 63 wyników po odfiltrowaniu
Filtry wybranego katalogu
Wyniki wyszukiwania dla: KUPONY KOROZYJNE
-
Electrochemical synthesis of 2D copper coordination-polymers: Layer-stacking deviation induced by the solvent and its effect on the adsorptive properties
PublikacjaA 2D Cu-based Metal-Organic Framework (MOF), namely copper-terephthalate (Cu(1,4-BDC)), was successfully synthesized by electrochemical method for effective methylene blue (MB) sorption from aqueous solutions. The composition, morphology, and the presence of functional groups in the obtained material were verified by Fourier Transform Infrared spectroscopy (FTIR), Powder X-Ray Diffraction (PXRD), Thermal (TGA), and Elemental (EA)...
-
The Effect of the Selection of Three-Dimensional Random Numerical Soil Models on Strip Foundation Settlements
PublikacjaThis paper delivers a probabilistic attempt to prove that the selection of a random three-dimensional finite element (FE) model of a subsoil affects the computed settlements. Parametricanalysis of a random soil block is conducted, assuming a variable subsoil Young’s modulus inparticular finite elements. The modulus is represented by a random field or different-sized setsof random variables; in both cases, the same truncated...
-
All-gather Algorithms Resilient to Imbalanced Process Arrival Patterns
PublikacjaTwo novel algorithms for the all-gather operation resilient to imbalanced process arrival patterns (PATs) are presented. The first one, Background Disseminated Ring (BDR), is based on the regular parallel ring algorithm often supplied in MPI implementations and exploits an auxiliary background thread for early data exchange from faster processes to accelerate the performed all-gather operation. The other algorithm, Background Sorted...
-
Smart Innovation Engineering Using Set of Experience and Decisional DNA
PublikacjaKnowledge-based Engineering Systems are founded upon integration of knowledge into computer systems and are one of the core requirements for the future Industry 4.0. Since the fourth industrial revolution is passing through the developing phase, implementation of Cyber-Physical Production Systems require more realistic approach. Knowledge Management and Knowledge Engineering plays an important role in manufacturing industries facing...
-
A Computationally Efficient Model for Predicting Successful Memory Encoding Using Machine-Learning-based EEG Channel Selection
PublikacjaComputational cost is an important consideration for memory encoding prediction models that use data from dozens of implanted electrodes. We propose a method to reduce computational expense by selecting a subset of all the electrodes to build the prediction model. The electrodes were selected based on their likelihood of measuring brain activity useful for predicting memory encoding better than chance (in terms of AUC). A logistic...
-
Regulated Control of the Assembly and Diversity of LPS by Noncoding sRNAs
PublikacjaThe outer membrane (OM) of Gram-negative bacteria is asymmetric due to the presence of lipopolysaccharide (LPS) facing the outer leaflet of the OM and phospholipids facing the periplasmic side. LPS is essential for bacterial viability, since it provides a permeability barrier and is a major virulence determinant in pathogenic bacteria. In Escherichia coli, several steps of LPS biosynthesis and assembly are regulated by the RpoE...
-
Gender and Labor Market Situation among Technical University Graduates in Poland
PublikacjaThe aim of article is to analyse the professional situation of technical university graduates in Poland, focusing on the gender as the key impact factor. The research problem was to examine the influence of gender on the employee’s professional situation among technical university graduates in Poland. Empirical data was gained as a result of six annual quantitative research projects, conducted in the years 2012‑2017 on a total...
-
Bearing estimation using double frequency reassignment for a linear passive array
PublikacjaThe paper demonstrates the use of frequency reassignment for bearing estimation. For this task, signals derived from a linear equispaced passive array are used. The presented method makes use of Fourier transformation based spatial spectrum estimation. It is further developed through the application of two-dimensional reassignment, which leads to obtaining highly concentrated energy distributions in the joint frequency-angle domain...
-
Stable nanoconjugates of transferrin with alloyed quaternary nanocrystals Ag–In–Zn–S as a biological entity for tumor recognition
PublikacjaOne way to limit the negative effects of anti-tumor drugs on healthy cells is targeted therapy employing functionalized drug carriers. Here we present a biocompatible and stable nanoconjugate of transferrin anchored to Ag-In-Zn-S quantum dots modified with 11-mercaptoundecanoic acid (Tf-QD) as a drug carrier versus typical anticancer drug, doxorubicin. Detailed investigations of Tf-QD nanoconjugates without and with doxorubicin...
-
Communication and Load Balancing Optimization for Finite Element Electromagnetic Simulations Using Multi-GPU Workstation
PublikacjaThis paper considers a method for accelerating finite-element simulations of electromagnetic problems on a workstation using graphics processing units (GPUs). The focus is on finite-element formulations using higher order elements and tetrahedral meshes that lead to sparse matrices too large to be dealt with on a typical workstation using direct methods. We discuss the problem of rapid matrix generation and assembly, as well as...
-
Fabrication and Significant Photoelectrochemical Activity of Titania Nanotubes Modified with Thin Indium Tin Oxide Film
PublikacjaOrdered titanium dioxide nanotubes (TiO2NTs) modified with indium tin oxide (ITO) films were obtained via magnetron sputtering, in which ITO plate was used as a target, onto the as-anodized titania support followed by the calcination process. The morphology of fabricated material with deposited oxide was investigated using scanning electron microscopy. Raman and UV–Vis spectroscopies were utilized to characterize crystalline phase...
-
Investigation of the electrochemical behaviour of AA1050 aluminium alloy in aqueous alkaline solutions using Dynamic Electrochemical Impedance Spectroscopy
PublikacjaThe paper presents the electrochemical behaviour of aluminium alloy AA1050 in aqueous alkaline media in the pH range 14–8.5. Electrochemical study was applied in order to obtain comprehensive information on the mechanism and kinetics of the process of anodic dissolution of aluminium, supplemented by monitoring of surface topography using an electron microscope. The corrosion rate of AA1050 increases with increasing concentration...
-
C-1311 (Symadex), a potential anti-cancer drug, intercalates into DNA between A and G moieties. NMR-derived and MD-refined stereostructure of the d(GAGGCCTC) 2 :C-1311 complex
PublikacjaImidazoacridinone C-1311 (Symadex®) is an antitumor agent which has been recommended for Phase II clinical trials a few years ago. Previously, it was shown experimentally that during the initial stage of its action C-1311 forms stable intercalation complexes with DNA duplexes. Herein, a NMR-derived stereostructure of d(GAGGCCTC)2:C-1311 complex was reported. The ligand was found locating itself between A and G moieties, forming...
-
Usefulness of separation techniques for identification and determination of Oxygenated Volatile Organic Compounds used in process analytics of water and wastewater
PublikacjaW pracy przedstawiono przegląd i porównanie metodyk identyfikacji i oznaczania Lotnych Związków Tlenoorganicznych (LZT). Porównano metodyki klasyczne umożliwiające oznaczanie wybranej grupy związków chemicznych należących do LZT lub dokonywanie oznaczeń sumarycznej zawartości z metodykiami wykorzystującymi techniki rozdzielania. Lotne związki tlenoorganicze, do których zaliczane są aldehydy, alkohole, ketony, estry, etery oraz...
-
Effects of deviations from thermo-rheologically simple behavior of asphalt mixes in creep on developing of master curves of their stiffness modulus
PublikacjaThe paper presents the deviations from the thermo-rheologically simple behavior of asphalt mixes and their effects on the developing of master curves of stiffness modulus. Eleven different mixes were tested in three point bending test under constant load at temperatures –20°C, –10 °C and 0 °C, and in some cases at +10 °C. The test method was developed at the Gdansk University of Technology, Poland. The applied stress level was...
-
Thin layer of ordered boron-doped TiO2 nanotubes fabricated in a novel type of electrolyte and characterized by remarkably improved photoactivity
PublikacjaThis paper reports a novel method of boron doped titania nanotube arrays preparation by electrochemical anodization in electrolyte containing boron precursor – boron trifluoride diethyl etherate (BF3 C4H10O), simultaneously acting as an anodizing agent. A pure, ordered TiO2 nanotubes array, as a reference sample, was also prepared in solution containing a standard etching compound: ammonium fluoride. The doped and pure titania...
-
Immobilization on magnetic nanoparticles of therecombinant trehalose synthase from Deinococcusgeothermalis
PublikacjatIn our study the gene encoding trehalose synthase from Deinococcus geothermalis was cloned and overexpressed inEscherichia coli Rosetta (DE3)pLysS. Wild-type trehalose synthase has been purified from host protein after cell dis-ruption and precipitation at 20% ammonium sulphate saturation. Recombinant trehalose synthase was immobilizedonto glutaraldehyde activated silanized magnetic ferrous-ferric oxide by using covalent binding...
-
A System for Heart Sounds Classification
PublikacjaThe future of quick and efficient disease diagnosis lays in the development of reliable non-invasive methods. As for the cardiac diseases – one of the major causes of death around the globe – a concept of an electronic stethoscope equipped with an automatic heart tone identification system appears to be the best solution. Thanks to the advancement in technology, the quality of phonocardiography signals is no longer an issue. However,...
-
Antibiotic-sterol interactions provide insight into the selectivity of natural aromatic analogues of amphotericin B and their photoisomers
PublikacjaAromatic heptaene macrolides (AHMs) belong to the group of polyene macrolide antifungal antibiotics. Members of this group were the first to be used in the treatment of systemic fungal infections. Amphotericin B (AmB), a non-aromatic representative of heptaene macrolides, is of significant clinical importance in the treatment of internal mycoses. It includes the all-trans heptaene chromophore, whereas the native AHMs contain two...
-
Reliable EM-driven size reduction of antenna structures by means of adaptive penalty factors
PublikacjaMiniaturization has become of paramount importance in the design of modern antenna systems. In particular, compact size is essential for emerging application areas such as internet of things, wearable and implantable devices, 5G technology, or medical imaging. On the other hand, reduction of physical dimensions generally has a detrimental effect on antenna performance. From the perspective of numerical optimization, miniaturization...
-
Two-step mechanism of J-domain action in driving Hsp70 function
PublikacjaJ-domain proteins (JDPs), obligatory Hsp70 cochaperones, play critical roles in protein homeostasis. They promote key allosteric transitions that stabilize Hsp70 interaction with substrate polypeptides upon hydrolysis of its bound ATP. Although a recent crystal structure revealed the physical mode of interaction between a J-domain and an Hsp70, the structural and dynamic consequences of J-domain action once bound and how Hsp70s...
-
Decomposition of halogenated nucleobases by surface plasmon resonance excitation of gold nanoparticles
PublikacjaHalogenated uracil derivatives are of great interest in modern cancer therapy, either as chemotherapeutics or radiosensitisers depending on their halogen atom. This work applies UV-Vis spectroscopy to study the radiation damage of uracil, 5-bromouracil and 5- uorouracil dissolved in water in the presence of gold nanoparticles upon irradiation with an Nd:YAG ns-pulsed laser operating at 532nm at dierent uences. Gold nanoparticles...
-
Human System Interaction in Review: Advancing the Artificial Intelligence Transformation
PublikacjaThe industrial advancement of human society has been fundamentally driven by diverse ‘systems’ that facilitate ‘human interaction’ within physical, digital, virtual, social and artificial environments, and upon the hyper-connected layers of system-system interactions across these environments. The research and practice of Human System Interaction (HSI) has undergone exponential development due to the enhanced capabilities, increased...
-
Deposition and Electrical and Structural Properties of La0.6Sr0.4CoO3 Thin Films for Application in High-Temperature Electrochemical Cells
PublikacjaLow-temperature deposition of electroceramic thin films allows the construction of new devices and their integration with existing large-scale fabrication methods. Developing a suitable low-cost deposition method is important to further advance the development of microdevices. In this work, we deposited a 1-lm-thick La0.6Sr0.4CoO3d (LSC) perovskite with high electrical conductivity on sapphire substrates at 400C and analyzed its...
-
Expedited Geometry Scaling of Compact Microwave Passives by Means of Inverse Surrogate Modeling
PublikacjaIn this paper, the problem of geometry scaling of compact microwave structures is investigated. As opposed to conventional structures (i.e., constructed using uniform transmission lines), re-design of miniaturized circuits (e.g., implemented with artificial transmission lines, ATSs) for different operating frequencies is far from being straightforward due to considerable cross-couplings between the circuit components. Here, we...
-
The Use of Big Data in Regenerative Planning
PublikacjaWith the increasing significance of Big Data sources and their reliability for studying current urban development processes, new possibilities have appeared for analyzing the urban planning of contemporary cities. At the same time, the new urban development paradigm related to regenerative sustainability requires a new approach and hence a better understanding of the processes changing cities today, which will allow more efficient...
-
Multicomponent ionic liquid CMC prediction
PublikacjaWe created a model to predict CMC of ILs based on 704 experimental values published in 43 publications since 2000. Our model was able to predict CMC of variety of ILs in binary or ternary system in a presence of salt or alcohol. The molecular volume of IL (Vm), solvent-accessible surface (Sˆ), solvation enthalpy (DsolvGN), concentration of salt (Cs) or alcohol (Ca) and their molecular volumes (Vms and Vma, respectively) were chosen...
-
Cost-efficient design optimization of compact patch antennas with improved bandwidth
PublikacjaIn this letter, a surrogate-assisted optimization procedure for fast design of compact patch antennas with enhanced bandwidth is presented. The procedure aims at addressing a fundamental challenge of the design of antenna structures with complex topologies, which is simultaneous adjustment of numerous geometry parameters. The latter is necessary in order to find a truly optimum design and cannot be executed-at the level of high-fidelity...
-
Molecular epidemiology of Serratia marcescens in two hospitals in Danzig, Poland, over a 5-year period.Molecular epidemiology of Serratia marcescens in two hospitals in Gdańsk, Poland, over a 5-year period.
PublikacjaW pracy badano zmiany populacji Serratia marcescens w ciągu 5 lat w dwóch szpitalach klinicznych Gdańska. Posłużono się wartościami MIC, wynikami typowania genetycznego RAPD-PCR, PFGE i nową metodą ADSRRS-fingerprinting oraz analizą beta-laktamaz o rozszerzonym spektrum substratowym (ESBL). Dzięki określeniu lekowrażliwości na najnowsze antybiotyki beta-laktamowe wykryto fenotypy wykazujące derepresję cefalosporynazy AmpC u 23%...
-
Opracowanie deskryptora nawierzchni drogowej do oceny oporu toczenia opon samochodowych
PublikacjaNa początku niniejszej pracy pt. „Opracowanie deskryptora nawierzchni drogowej do oceny oporu toczenia opon samochodowych” przedstawiono zagadnienia dotyczące oporów ruchu pojazdu. Omówiono metody zarówno drogowe, jak i laboratoryjne badań oporu toczenia opon samochodowych. Zaprezentowano przykładowe wartości współczynników oporu toczenia opon na różnych rodzajach nawierzchni. Kolejno omówiono metody pomiaru tekstury nawierzchni....
-
A new B-D-galactosidase with a low temperature optimum isolated from the Antarctic Arthrobacter sp. 20B: gene cloning, purification and characterization.
PublikacjaA psychrotrophic bacterium producing a coldadaptedB-galactosidase upon growth at low temperatureswas classiWed as Arthrobacter sp. 20B. A genomic DNAlibrary of strain 20B introduced into Escherichia coliTOP10F' and screening on X-Gal (5-bromo-4-chloro-3-indolyl-B-D-galactopyranoside)-containing agar plates ledto the isolation of B-galactosidase gene. The B-galactosidasegene (bgaS) encoding a protein of 1,053 amino acids,with a...
-
The experience of movement in orbital space architecture: A narrative of weightlessness
PublikacjaBased upon a combination of architectural theories, the knowledge of space environment, and psychology of isolated and confined environments, this qualitative research aims to study orbital space settlement in a way to get the built space congenial to the human experience of movement. In this sense, sensors, self-propulsion or mechanical actuators, the inhabitant’s mental and visual capacity for movement, as well as the represented...
-
Thermodynamics and Intermolecular Interactions of Nicotinamide in Neat and Binary Solutions: Experimental Measurements and COSMO-RS Concentration Dependent Reactions Investigations
PublikacjaIn this study, the temperature-dependent solubility of nicotinamide (niacin) was measured in six neat solvents and five aqueous-organic binary mixtures (methanol, 1,4-dioxane, acetonitrile, DMSO and DMF). It was discovered that the selected set of organic solvents offer all sorts of solvent effects, including co-solvent, synergistic, and anti-solvent features, enabling flexible tuning of niacin solubility. In addition, differential...
-
Immunization with an anti-idiotypic antibody against the broadly lipopolysaccharide-reactive antibody WN1 222-5 induces Escherichia coli R3-core-type specific antibodies in rabbits
PublikacjaThe mouse monoclonal antibody (mAb) WN1 222-5 recognizes a carbohydrate epitope in the inner core region of LPS that is shared by all strains of Escherichia coli and Salmonella enterica and is able to neutralize their endotoxic activity in vitro and in vivo. Immunization of mice with mAb WN1 222-5 yielded several anti-idiotypic mAbs one of which (mAb S81-19) competitively inhibited binding of mAb WN1 222-5 to E. coli and Salmonella...
-
Molecularly imprinted polymers for the detection of volatile biomarkers
PublikacjaIn the field of cancer detection, the development of affordable, quick, and user-friendly sensors capable of detecting various cancer biomarkers, including those for lung cancer (LC), holds utmost significance. Sensors are expected to play a crucial role in the early-stage diagnosis of various diseases. Among the range of options, sensors emerge as particularly appealing for the diagnosis of various diseases, owing to their cost-effectiveness,...
-
The experience of movement in orbital space architecture: A narrative of weightlessness
PublikacjaBased upon a combination of architectural theories, the knowledge of space environment, and psychology of isolated and confined environments, this qualitative research aims to study orbital space settlement in a way to get the built space congenial to the human experience of movement. In this sense, sensors, self-propulsion or mechanical actuators, the inhabitant’s mental and visual capacity for movement, as well as the represented...
-
Comprehensive Evaluation of the Biological Properties of Surface-Modified Titanium Alloy Implants
PublikacjaAn increasing interest in the fabrication of implants made of titanium and its alloys results from their capacity to be integrated into the bone system. This integration is facilitated by different modifications of the implant surface. Here, we assessed the bioactivity of amorphous titania nanoporous and nanotubular coatings (TNTs), produced by electrochemical oxidation of Ti6Al4V orthopedic implants’ surface. The chemical composition...
-
Effective Equations for the Optimum Seismic Gap Preventing Earthquake-Induced Pounding between Adjacent Buildings Founded on Different Soil Types
PublikacjaThe best approach to avoid collisions between adjacent structures during earthquakes is to provide sufficient spacing between them. However, the existing formulas for calculating the optimum seismic gap preventing pounding were found to provide inaccurate results upon the consideration of different soil types. The aim of this paper is to propose new equations for the evaluation of the sufficient in-between separation gap for buildings...
-
Integrated plant-wide modelling for evaluation of the energy balance and greenhouse gas footprint in large wastewater treatment plants
PublikacjaModern wastewater treatment plants (WWTPs) should maintain a balance between three combined sustainability criteria, including effluent quality, energy performance and greenhouse gas (GHG) emissions. All of these criteria were considered in the integrated plant-wide model developed in this study. The proposed model incorporates new features, including: (i) the addition of associated facilities to the overall energy balance and...
-
DC and AC Conductivity, Biosolubility and Thermal Properties of Mg-Doped Na2O–CaO–P2O5 Glasses
PublikacjaBioactive glasses have recently been extensively used to replace, regenerate, and repair hard tissues in the human body because of their ability to bond with living tissue. In this work, the effects of replacing Na2O with MgO on the electrical, biosolubility, and thermal properties of the target glass 10Na2O–60P2O5–30CaO (in mol%) were investigated. The electrical properties of the glasses were studied with the impedance spectroscopy...
-
Efficient and robust quadratures for isogeometric analysis: Reduced Gauss and Gauss–Greville rules
PublikacjaThis work proposes two efficient quadrature rules, reduced Gauss quadrature and Gauss–Greville quadrature, for isogeometric analysis. The rules are constructed to exactly integrate one-dimensional B-spline basis functions of degree p, and continuity class C^{p−k}, where k is the highest order of derivatives appearing in the Galerkin formulation of the problem under consideration. This is the same idea we utilized in Zou et al....
-
IFI16 Impacts Metabolic Reprogramming during Human Cytomegalovirus Infection
PublikacjaCellular lipid metabolism plays a pivotal role in human cytomegalovirus (HCMV) infection, as increased lipogenesis in HCMV-infected cells favors the envelopment of newly synthesized viral particles. As all cells are equipped with restriction factors (RFs) able to exert a protective effect against invading pathogens, we asked whether a similar defense mechanism would also be in place to preserve the metabolic compartment from HCMV...
-
Rapid Variable-Resolution Parameter Tuning of Antenna Structures Using Frequency-Based Regularization and Sparse Sensitivity Updates
PublikacjaGeometry parameter tuning is an inherent part of antenna design process. While most often performed in a local sense, it still entails considerable computational expenses when carried out at the level of full-wave electromagnetic (EM) simulation models. Moreover, the optimization outcome may be impaired if good initial design is not available. This paper proposes a novel approach to fast and improved-reliability gradient-based...
-
Investigation method of large-volume tire with mobile test rig
PublikacjaThe goal of this research is to develop the tire test method and mobile tire test rig. The test rig enables measurement of tire properties as stiffness and viscous damping in vertical direction, and tire–ground characteristics on the asphalt rigid surface. The tire-ground characteristics are measured by force and a torque measurement hub. The design, calibration and the algorithm for calculating the forces in the wheel center are...
-
Identyfikacja i izolacja genu kodującego zaadaptowaną do zimna β-galaktozydazę Paracoccus sp. = Identification and izolation of the gene encoding cold-active β-galactosidase from paracoccus sp.
PublikacjaZaprezentowane badania były prowadzone u eehi wyizolowania ze środo¬wiska organizmu psychrofilnego, zdolnego do hydrolizy laktozy w niskiej tempe¬raturze, oraz zidentyfikowania genu kodującego (i-galaktozydazę zaadaptowaną do zimna.Poszukiwan gen został w izolowany z psychrofilnego szczepu autarkicz¬nego Paracoccus sp. 321). Na podstawie sekwencji nukleotydowej genu kodują¬cego fS-galaktozdaze ustalono skład aminokwasów),...
-
SEI Growth and Depth Profiling on ZFO Electrodes by Soft X-Ray Absorption Spectroscopy
PublikacjaZnFe2O4 (ZFO) Li-ion batteries (LIBs) represent a reliable, affordable, and safe energy storage technology for use in portable application. However, current LIB active materials (graphite, lithium/transition metal spinel or layered oxides, olivine structures) can store only limited energy since they rely on insertion storage based on solid-state host-guest interactions. Moreover, performances and durability of the cells are strongly...
-
An overview of the cognitive and biological effects of city nighttime illumination including a London case study
PublikacjaCurrent scientific research demonstrates how critical the effects of city nighttime illumination are upon cognitive and biological health1 – which needs to be adequately acknowledged, understood and addressed by conscious cities and the plans they develop. Until recent decades, the design of nighttime lighting was determined mostly by electrical engineers who often applied technical standards to meet the requirements of vehicle-focused...
-
Experiencing historic waterways and water landscapes of the Vistula River Delta
PublikacjaThe paper gives insights into the characteristics of Vistula River Delta water landscapes, referring to the process of creating land out of water by Polish, Dutch and German settlers. Based on this, the paper presents an integrated strategy formed upon studies in cultural geography and aesthetics, and focused on enhancing the unique characteristics of the region and its rediscovery by tourism. The long process of constructing Vistula...
-
Gold nanoparticles for cancer radiotherapy: a review
PublikacjaRadiotherapy is currently used in around 50% of cancer treatments and relies on the deposition of energy directly into tumour tissue. Although it is generally effective, some of the deposited energy can adversely affect healthy tissue outside the tumour volume, especially in the case of photon radiation (gamma and X-rays). Improved radiotherapy outcomes can be achieved by employing ion beams due to the characteristic energy deposition...
-
Approximation Strategies for Generalized Binary Search in Weighted Trees
PublikacjaWe consider the following generalization of the binary search problem. A search strategy is required to locate an unknown target node t in a given tree T. Upon querying a node v of the tree, the strategy receives as a reply an indication of the connected component of T\{v} containing the target t. The cost of querying each node is given by a known non-negative weight function, and the considered objective is to minimize the total...