Selecting particular columns from large datasets (csv) using R Studio?

So I have large number of csv files (100+) in a directory with same structure and column names. The data is in time series and there are approx 30 columns/file. However i only want to aggregate...

08 February 2021 245 5 View

How much pre-PCR dilution of mixed-template DNA extracted from pollen (honey) is appropriate for Metabarcoding?

I'm working on pollen DNA metabarcoding to identify the floral composition of honey. How much pre-PCR dilution of mixed-template DNA extracted from pollen (honey) is appropriate for the...

28 December 2020 9,132 1 View

How to add two vertical and parallel Fresnel reflection coefficients to retrieve overall reflection coefficient for a right hand circular wave?

I have a problem in which a right hand circular polarized wave (GPS wave) encounters an ideal smooth plane obliquely, and then is reflected off that. To solve this kind of problems, the wave is...

28 December 2020 2,271 3 View

Which is better to focus on teaching or research for a good academic life and Why?

Which is better to focus on teaching or research for For a good academic life and Why?

26 December 2020 5,737 9 View

Is ag paste suitable for back contact on silicon wafer? or i should deposit al on the back surface using pvd or plasma sputtering?

Fabricating silicon solar cell

22 December 2020 4,906 7 View

Which renewable source is the best ?

wind hydro solar etc.

21 December 2020 6,360 16 View

Why is light pure energy?

light is pure because the light is the simplest electromagnetic construct but the energy of any object is also of the same kind.

20 December 2020 207 4 View

How to handle Missing Values for Skipped Questions (Systematic Missing) in R ?

10 December 2020 435 4 View

What is the best industrial emulsifier to make silicon oil in water emulsion?

I need to make long-lasting stable emulsions of 6 wt. % percent silicon oil in DI water. The previousely made emulsions using Tween and Span Emulsifiers did not remain stable after a week.

31 October 2020 3,568 3 View

Carbon Emission calculation factors ?

I am thinking about writing a paper on carbon emissions based on electricity consumption data from some buildings. From a research perspective, which factors should i specially focus while...

09 October 2020 4,142 3 View

How to increase a model accuracy ?

dear community, my model is based feature extraction from non stationary signals using discrete Wavelet Transform and then using statistical features then machine learning classifiers in order to...

03 March 2021 6,994 5 View

New Journal, "Integrative Psychological and Behavioral Science" -- do you not know, and have you not seen, this done before?

Question to you and THEM, the New Journal, "Integrative Psychological and Behavioral Science" -- do you not know, and have you not seen, this done before? There appears to be a core problem for...

02 March 2021 3,024 2 View

OpenBCI eeg--has anyone used them?

I'm looking to try out an off-the-shelf EEG set for some exploratory work. Curious if anyone has used the OpenBCI, and how much set-up work is required. I've heard they are more difficult to get...

01 March 2021 4,128 3 View

Isolates of Hymenoscyphus fraxineus?

Dear Dr. Cai, my name is Simone Prospero and I work in the team of Phytopathology at the Swiss Federal Institute for Forest Snow and Landscape Research (WSL;...

01 March 2021 1,133 1 View

How to eliminate Steady state error from Reinforcement learning genetic algorithm code?

The following code (see 1st 2 images attached) is used to produce PID controller values that are designed to control the system (G). The code finds the PID controller values (noted as k) by using...

28 February 2021 6,560 14 View

Can Ethovision store the generated data and video recordings directly to NAS system?

The size of data generated by Ethovision is huge. Having NAS system for data storage seems to be a good option, I am wondering whether Ethovision can directly store the data to the NAS system...

27 February 2021 6,350 2 View

LEDs on Vis Light photo degradation of MB water sol via N doped TiO2 in a mini flume?

Good day to all, I have no experience with light emitting diodes. I am building a glass mini flume to demonstrate the photo degradation of Methylene Blue in water running over self cleaning...

26 February 2021 4,026 5 View

CGA 300 Regulator for CO2 cylinder?

Has anyone ever tried to deliver CO2 with a CGA 300 regulator? I know that a CGA 320 regulator is standard for CO2. The issue is that I currently do not have any free CGA 320 regulators. I also...

25 February 2021 3,292 3 View

What are the patterns of human behavior that lead to COVID-19 infections?

Does data from contact tracing help in establishing patterns of behavior and social interactions that lead to infections? There are cases here in the Philippines where patients have no travel...

25 February 2021 9,002 13 View

How to interpolate from a time-series database ?

Hi, I am having trouble with a problem, in the field of Optimal Control and the generation of optimal time-series. Let's consider a system, whose dynamics are represented by dx/dt =...

24 February 2021 9,105 2 View