The time machine

The research subject is the process of economic and mathematical modelling of time series characterizing the bitcoin exchange rate volatility, based on the use of artificial neural networks. The purpose of the work is to search and scientifically substantiate the tools and mechanisms for developing prognostic estimates of the crypto currency market development. The paper considers the task of financial time series trend forecasting using the LSTM neural network for supply chain strategies.

5p longtimenosee09 08-04-2024 10 1   Download

This article presents a study on the investigation of the effects of the input parameters on the cutting speed in machining 90CrSi tool steel using wire cut electrical discharge machining (EDM).

6p lucastanguyen 01-06-2020 41 2   Download

In this paper we present a new heuristic algorithm to minimize the total completion time (Makespan) in permutation flow shop scheduling of ‘n’ jobs and ‘m’ machines by using harmonic triangle.

6p lucastanguyen 01-06-2020 15 2   Download

A state of the art instrumented Drop Weight Impact Tester Machine was developed in Iran University of Science and Technology which measures the energy absorption of composite materials under impact load.

8p tohitohi 19-05-2020 19 1   Download

(BQ) In this research work two different materials have been used as work pieces. These EN8 and D3 steel materials have been machined in an Electrical discharge machine which has wide application in Industry fields. The important process parameters that have been selected are peak current, pulse on time, die electric pressure and tool diameter. The outputs responses are material removal rate (MRR), tool wear rate (TWR) and surface roughness (SR).

11p xuanphuongdhts 27-03-2017 48 2   Download

(BQ) Electrical discharge machining (EDM) is a widespread process which works very effectively in machining of difficult-to-cut materials and alloys in die and aerospace industries with high dimensional accuracies. However, this capability could be deteriorated due to electrode wear leading to decrease of process productivity. In this study, the effect of machining parameters of EDM process including on-time, current, voltage, the engaging time between workpiece and electrode, and pre-EDM roughing on electrode wear were experimentally investigated.

4p xuanphuongdhts 27-03-2017 49 2   Download

(BQ) In this paper, working current, working voltage, oil pressure, spark gap Pulse On Time and Pulse Off Time on Material Removal Rate (MRR) and Surface Finish (Ra) has been studied. Empirical models for MRR and Ra have been developed by conducting a designed experiment based on the Grey Relational Analysis. Genetic Algorithm (GA) based multi-objective optimization for maximization of MRR and minimization of Ra has been done by using the developed empirical models. Optimization results have been used for identifying the machining conditions.

10p xuanphuongdhts 27-03-2017 42 2   Download

(BQ) This paper is devoted to a study of the influences of EDM parameters on surface roughness for machining of 40CrMnNiMo864 tool steel (AISI P20) which is widely used in the production of plastic mold and die. The selected EDM parameters were pulsed current (8, 16 and 24 A), pulse time (2, 3, 4, 6, 12, 24, 48 and 100 s) and pulse pause time (2 and 3s). It was observed that surface roughness of workpiece and electrode were influenced by pulsed current and pulse time, higher values of these parameters increased surface roughness.

4p xuanphuongdhts 27-03-2017 52 4   Download

(BQ) This study was made only for the finish stages and has been carried out on the influence of five design factors: intensity supplied by the generator of the EDM machine (I), pulse time (ti), duty cycle (η), open-circuit voltage (U) and dielectric flushing pressure (P), over the two previously mentioned response variables. This has been done by means of the technique of design of experiments (DOE), which allows us to carry out the above-mentioned analysis performing a relatively small number of experiments.

8p xuanphuongdhts 27-03-2017 55 2   Download

(BQ) Surface integrity and dimensional accuracy remain critical concern in Electrical Discharge Machining (EDM). The current research work aims at investigating the influence of various EDM process parameters like pulse current (Ip), pulse-on time (Ton), tool work time (Tw) and tool lift time (Tup) on various aspects of surface integrity like white layer thickness (WLT), surface crack density (SCD) and surface roughness (SR). The dimensional accuracy, characterized by over cut (OC), has also been studied in the similar way.

13p xuanphuongdhts 27-03-2017 47 2   Download

(BQ) The adequate selection of manufacturing conditions is one of the most important aspects to take into consideration in the die-sinking electrical discharge machining (EDM) of conductive ceramics, as these conditions are the ones that are to determine such important characteristics as: surface roughness, electrode wear (EW) and material removal rate, among others. In this work, a study was carried out on the influence of the factors of intensity (I), pulse time (ti) and duty cycle (η) over the listed technological characteristics.

7p xuanphuongdhts 27-03-2017 38 2   Download

(BQ) The present work deals with the comparison of the MRR for EN19 and EN41 material in a die sinking EDM machine. The various input factors like Pulse ON time, Pulse OFF time, Discharge current and voltage were considered as the input processing parameters, while the MRR is considered as the output. Optimization using Taguchi method was performed to predict the best combination of inputs towards maximum output.

7p xuanphuongdhts 27-03-2017 37 2   Download

(BQ) The article presents an idea about the effect of the various input process parameters like Pulse ON time, Pulse OFF time, Discharge Current and Voltage over the Surface Roughness for an EN41 material. Here, 5 different output parameters concerned with surface roughness like Ra, Rq, Rsk, Rku and Rsm are taken and optimized accordingly, using the Grey-Taguchi method.

8p xuanphuongdhts 27-03-2017 61 4   Download

In the past, we presented tutorials called “Introduction to Statistical Machine Translation”, aimed at people who know little or nothing about the field and want to get acquainted with the basic concepts. This tutorial, by contrast, goes more deeply into selected topics of intense current interest. We aim at two types of participants: 1. People who understand the basic idea of statistical machine translation and want to get a survey of hot-topic current research, in terms that they can understand. 2.

1p hongphan_1 15-04-2013 64 3   Download

We can only do a linear search on an unsorted array, but on a sorted array we can do a binary search. In this chapter we will study two different algorithms for searching, linear search and binary search. In linear search we look through an unordered list until we find the item we are looking for. The length of time it takes to look up something using a linear search will depend upon the size of the list. Imagine trying to look up a name in a telephone directory if it was not alphabetized (sorted). If we were to use...

9p linhtk93 15-04-2013 52 3   Download

Bạn có thể cho rằng các backup hàng giờ là khá thừa. Apple không cung cấp cho bạn một cách thuận tiện để thay đổi lịch trình backup mặc định. Tuy nhiên có một cách dễ dàng khác để có thể thực hiện được điều đó. Ở đây chúng tôi sẽ giới thiệu cho các bạn hai cách có thể thay đổi được lịch trình backup hàng giờ này. Thay đổi các file hệ thống Nếu bạn chỉ muốn thay đổi khoảng thời gian mặc định và không lịch trình bất cứ thứ gì khác, hãy thực hiện theo phương...

3p bibocumi27 14-01-2013 59 4   Download

Sử dụng tiện ích Backup của MobileMe .Đối với hầu hết người dùng, khi nói đến việc backup trong Mac chúng ta thường nghĩ đến Time Machine. Tuy nhiên Apple còn có một ứng dụng backup khác mang tên Backup mà người dùng MobileMe có thể khai thác và sử dụng. Chính vì vậy mà trong bài viết này chúng tôi sẽ hướng dẫn cho các bạn cách sử dụng tiện ích này Backup để thực hiện backup. Cụ thể trong bài chúng ta sẽ đi xem xét cách sử dụng Backup để lưu thư mục chủ. Để làm được điều...

10p lulaula 28-10-2012 85 2   Download

Sao lưu thư viện ảnh iPhoto Bài viết giới thiệu cách sao lưu thư viện ảnh iPhoto ’11 trong máy Mac của bạn vào ổ đĩa cứng ngoài hay đĩa CD/DVD. Hệ thống bị hư có thể sẽ làm mất dữ liệu, đặc biệt là tất cả hình ảnh mà bạn lưu trong máy. Do đó, người dùng máy Mac nên thường xuyên sử dụng tính năng Time Machine để sao lưu ảnh vào ổ đĩa cứng ngoài. Sao lưu vào ổ đĩa cứng ngoài Kết nối ổ đĩa cứng ngoài vào máy Mac của bạn rồi bật lên. Một...

4p tieuyeuquai456 08-10-2012 81 5   Download

ĐỀ VÀ ĐÁP ÁN KỲ THI THỬ ĐH NĂM 2011 MÔN: TIẾNG ANH – ĐẾ 7 Phần 1: Chọn từ có cách phát âm khác 1. A. see B. saw C. sort D. she 2. A. watching B. matches C. machine D. kitchen 3. A. time B. night C. living D. child 4. A. here B. where C. hair D. wear 5. A. new B. few C. sew D. chew Phần 2: Chọn đáp án đúng 6. .........you...........to the radio?” “Turn it off, please” A. Are / listening B. Do / listen C. Did / listened D. Is / listening 7....

7p sunderland246 14-07-2011 769 133   Download

Chuẩn bị một chương trình sao lưu hoàn hảo trên Mac Từ phiên bản Leopard trở lên, ứng dụng Time Machine dùng để giúp người dùng sao lưudữ liệu đã được Apple tích hợp sẵn vào trong bộ ứng dụng kèm theo miễn phí. Với Time Machine, người dùng hoàn toàn có thể thiết lập một chương trình sao lưu dữ liệu hoàn hảo để giúp cho dữ liệu trong máy tính của mình luôn được bảo vệ một cách tốt nhất....

7p xmen2525 25-04-2011 87 5   Download