Iskanje po katalogu digitalne knjižnice

Opis: The field of reinforcement learning shows promising results in recent publications for solving complex combinatorial problems. In this paper, an agent is trained to tackle the relocation problem that appears in various logistics systems. The relocation problem was formulated as an array that is accessible only from the top side. The agent has to relocate blocking SKUs and thus enable access to the SKU with the highest dispatch priority. We utilised the Deep Q-learning Network (DQN) to train the agent. Two case studies are presented – one with 1.2 ∙ 10 and another with 2 ∙ 10 possible states. The results display that the agents made a significantly better decision toward the learning process’s end than at the beginning
Ključne besede: relocation problem, reinforcement learning, DQN, multiple-deep, storage system
Objavljeno v DKUM: 14.03.2023; Ogledov: 135; Prenosov: 7
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Opis: Humanity has recently begun to realize that resources on Earth are not infinite and that, consequently, it is imperative for us to start to use them sustainably and renewably. Aligned with this mentality, forward osmosis has been rigorously studied in the past few decades with some commercially available products already on the market. This thesis used one of those products, namely, the Aquaporin HFFO 2 membrane module, and assessed its stability in sodium metabisulfite solution and high salinity without flowing solutions under long-term storage conditions. The sodium metabisulfite preservation part was devised to upgrade the existing guidelines for prolonged storage of fouled membranes and the osmotic drying project was looking at a scenario where the modules would be exposed to a salt solution on the draw side and no flowing wastewater on the feed side. The assessments were made on pristine HFFO 2 membrane modules and with RO water prepared on site. Their performance after exposure was measured with an internal quality control procedure, producing values for water flux, reverse salt flux, normalized reverse salt flux and temperature, which were later compared with the initial values. The findings show us that the sodium metabisulfite and increased salinity have a detrimental effect on the membrane inside of the module, but not enough to be considered damaged and would need to be discarded. More valuable results will be gained if the measurements are done on fouled membranes, as the biggest factor in increasing the lifetime of a module is preventing algal and bacterial growth
Ključne besede: forward osmosis, Aquaporin HFFO 2, sodium metabisulfite, osmotic drying, prolonged storage.
Objavljeno v DKUM: 24.09.2020; Ogledov: 595; Prenosov: 5
Celotno besedilo (3,09 MB)

Opis: This paper deals with the sedimentation of suspended load in the reservoirs. As an example the reservoir of the hydroelectric power plant Boštanj on the Sava River is shown. The objective of the described studies was to determine the quantity and type of deposited material in the reservoir during the selected time period. For this purpose, the mineral and chemical composition, and the concentration and the particle size of the suspended load at the intake of the water into the reservoir and at its outflow were examined. In order to determine the concentration of the suspended load, 24 water samples from the area of the intake and outflow from the reservoir were taken. At the same time the discharge of the Sava River was measured. Solid particles were removed from the water with the help of sedimentation and in the final stage of water evaporation. The results of the studies showed that the concentration of the suspended material was changing in relation to the location and the flow rate of the water. This ratio can be described with an exponential function. In suspended load composition carbonates, muscovite/illite and quartz dominate; however, chlorite was also found, as well as small quantities of plagioclase and organic detritus. With regard to the size of the particles the examined samples are classified as silt. It was determined that the concentration of the suspended load, at the same flow rate of water, at the intake into the reservoir is larger than at the outflow. The difference is represented by the material that was sedimented in the reservoir due to the decreased speed of the water as a result of the river's impoundment. A comparison of the composition of the samples from both collection sites showed that at the outflow site of the water from the reservoir there is a somewhat smaller share of carbonate grains and heavy minerals than at the intake site, and a higher content of organic detritus and clay particles can also be observed. Considering the actual discharge of water in the period between July 2006 and July 2007 and the examined ratio between the flow rate of the water and the quantity of suspended and deposited material, the total quantity of sedimented material in this period was estimated.
Ključne besede: suspended load, sedimentation, sediment transport, water storage reservoir
Objavljeno v DKUM: 05.06.2018; Ogledov: 1680; Prenosov: 68
Celotno besedilo (348,17 KB)
Gradivo ima več datotek! Več...

Opis: Diplomska naloga obravnava vpeljavo storitve, ki omogoča upravljanje diskovnih polj. Predstavljena je definicija pojmov, kot so diskovno polje, funkcije diskovnih polj, programsko definirani podatkovni center, programsko definirani pomnilnik. Opisane so glavne značilnosti rešitve IBM Tivoli Storage Productivity Center (TSPC), ki omogoča upravljanje heterogenih virov podatkov. Za konkretnega naročnika je bila opravljena analiza stanja, ki je pokazala, da je upravljanje več kot dvesto terabajtov podatkov nepregledno, reševanje težav zaradi razdrobljenosti upravljanja prepočasno in da obstaja visoko tveganje za izpad storitve. Definirana je bila storitev Upravljanje diskovnih polj. V nalogi so prikazane komponente prototipne rešitve in primeri poročil o obremenitvi tako stikal za diskovna polja kot tudi samih diskovnih polj. Storitev je vpeljana v uporabo in omogoča pravočasno zaznavo težav, alarmiranje v primeru neželenih dogodkov ter bistveno zmanjša napor izvajalcev storitve.
Ključne besede: upravljanje diskovnih polj, programsko definirano diskovno polje, IBM Tivoli Storage Productivity Center, sporazum o ravni storitve
Objavljeno v DKUM: 07.10.2016; Ogledov: 1193; Prenosov: 88
Celotno besedilo (2,24 MB)

Opis: V prispevku je predstavljen simulacijski model avtomatiziranega regalnega skladiščnega sistema z enojno pomično in večpomičnimi mizami. Glavni namen predstavljene raziskave je določitev zmogljivosti sistema z večpomičnimi mizami, glede na sistem z enojno pomično mizo. Slednje pomeni glavni delež in pomoč pri postopku načrtovanja avtomatiziranega regalnega skladiščnega sistema. Povečanje pretočne zmogljivosti transportno-skladiščnih enot je mogoče z uporabo sistema z večpomičnimi mizami, glede na sistem z enojno-pomično mizo. V inženirski praksi se največkrat uporablja sistem z enojno pomično mizo, ki temelji na dvojnem delovnem krogu, medtem ko sistem z večpomičnimi mizami temelji na štirikratnem in šestkratnem delovnem krogu. Problem se pojavi pri uporabi ustrezne upravljalne strategije, za zagotovitev pogoja o najmanjših vožnjah regalnega dvigala. V ta namen smo uporabili posebno domiselno metodo, poimenovano "Strategija x", ki razvrsča zaporedje skladiščnih in odpremnih zahtev, z namenom po minimizaciji povprečnega časa vožnje regalnega dvigala. Za ovrednotenje domiselne metode s sistemom večpomičnih miz smo uporabili tehniko diskretnih numeričnih simulacij. Rezultati simulacijske analize so pokazali očitno povečanje pretočnih zmogljivosti sistema z večpomičnimi mizami v primerjavi s sistemom enojne pomične mize.
Ključne besede: transport systems, high storage racks, automated warehousing, discrete event simulation, storage operation, performance analysis
Objavljeno v DKUM: 10.07.2015; Ogledov: 1374; Prenosov: 41
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