Search results for "muuttujat"

Hyperspectral UAV-Imagery and photogrammetric canopy height model in estimating forest stand variables

2017

Remote sensing using unmanned aerial vehicle (UAV) -borne sensors is currently a highly interesting approach for the estimation of forest characteristics. 3D remote sensing data from airborne laser scanning or digital stereo photogrammetry enable highly accurate estimation of forest variables related to the volume of growing stock and dimension of the trees, whereas recognition of tree species dominance and proportion of different tree species has been a major complication in remote sensing-based estimation of stand variables. In this study the use of UAV-borne hyperspectral imagery was examined in combination with a high-resolution photogrammetric canopy height model in estimating forest v…

A European Multi Lake Survey dataset of environmental variables, phytoplankton pigments and cyanotoxins

2018

Under ongoing climate change and increasing anthropogenic activity, which continuously challenge ecosystem resilience, an in-depth understanding of ecological processes is urgently needed. Lakes, as providers of numerous ecosystem services, face multiple stressors that threaten their functioning. Harmful cyanobacterial blooms are a persistent problem resulting from nutrient pollution and climate-change induced stressors, like poor transparency, increased water temperature and enhanced stratification. Consistency in data collection and analysis methods is necessary to achieve fully comparable datasets and for statistical validity, avoiding issues linked to disparate data sources. The Europea…

Visual Parameter Selection for Spatial Blind Source Separation.

2022

Analysis of spatial multivariate data, i.e., measurements at irregularly-spaced locations, is a challenging topic in visualization and statistics alike. Such data are inteGral to many domains, e.g., indicators of valuable minerals are measured for mine prospecting. Popular analysis methods, like PCA, often by design do not account for the spatial nature of the data. Thus they, together with their spatial variants, must be employed very carefully. Clearly, it is preferable to use methods that were specifically designed for such data, like spatial blind source separation (SBSS). However, SBSS requires two tuning parameters, which are themselves complex spatial objects. Setting these parameter…

Polynomial Regression and Measurement Error

2020

Many of the phenomena of interest in information systems (IS) research are nonlinear, and it has consequently been recognized that by applying linear statistical models (e.g., linear regression), we may ignore important aspects of these phenomena. To address this issue, IS researchers are increasingly applying nonlinear models to their datasets. One popular analytical technique for the modeling and analysis of nonlinear relationships is polynomial regression, which in its simplest form fits a "U-shaped" curve to the data. However, the use of polynomial regression can be problematic when the independent variables are contaminated with measurement error, and the implications of error can be m…

Fast and universal estimation of latent variable models using extended variational approximations

2022

AbstractGeneralized linear latent variable models (GLLVMs) are a class of methods for analyzing multi-response data which has gained considerable popularity in recent years, e.g., in the analysis of multivariate abundance data in ecology. One of the main features of GLLVMs is their capacity to handle a variety of responses types, such as (overdispersed) counts, binomial and (semi-)continuous responses, and proportions data. On the other hand, the inclusion of unobserved latent variables poses a major computational challenge, as the resulting marginal likelihood function involves an intractable integral for non-normally distributed responses. This has spurred research into a number of approx…

Maaston ja juoksunopeuden vaikutukset askelmuuttujiin suunnistusjuoksusuorituksessa

2014

Johdanto. Suunnistuksessa sekä fyysinen että taidollinen elementti vaikuttavat lopputulokseen. Suunnistusjuoksusuorituksessa taas edetään maastoon viitoitettua reittiä pitkin. Suunnistusjuoksu eroaa tasamaan juoksusta maaston jatkuvan vaihtelun, maastopohjan esteiden sekä korkeuserojen myötä. Nämä tekijät vaikuttavat myös suunnistusjuoksutekniikkaan. Tässä tutkimuksessa selvitettiin suunnistusjuoksun askelmuuttujien vaihtelua maastonosien sekä juoksunopeuden mukaan. Menetelmät. Tutkimukseen osallistui 10 miessuunnistajaa. Tutkimukset suoritettiin kahtena päivänä siten, että ensimmäinen päivä sisälsi antropometrisia mittauksia sekä suoran hapenottokykytestin juoksumatolla (VO2max -testi). Yh…

Hybrid evolutionary multi-objective optimization with enhanced convergence and diversity

2011

The Choice of Control Variables : How Causal Graphs Can Inform the Decision

2022

Control variables have a central role when empirical data are used to support causal claims in management research. The current literature has been intransparent in so far as to how control variables should be chosen, how many control variables should be chosen and whether a potential control variable should be included. Causal diagrams provide a transparent framework on how to select control variables for causal identification. This article delineates how causal graphs can inform researchers in leadership and management in finding the correct set of control variables and possible solutions in the case that causal identification is not possible or when causal identification requires unobser…

Osakemarkkinoiden ja reaalitalouden välinen kausaalisuus

1999

Muuttujat viidesluokkalaisten matematiikassa

2011

Algebran on useissa tutkimuksissa havaittu olevan oppilaille hankala aihe. Kuitenkin sen opettamisesta tavanomaista aiemmin on saatu myönteisiä kokemuksia. Tämä tutkimus selvitti viidesluokkalaisten valmiuksia käsitellä muuttujia matematiikassa. Aiempien tutkimusten mukaan algebran oppimista helpottavia keskeisiä seikkoja ovat muun muassa kyky merkitä muuttuja, käsitys muuttujasta sekä kyky ratkaista muuttujia sisältäviä tehtäviä. Nämä seikat olivat perusta tämän tutkimuksen ongelmille. Lisäksi selvitettiin yleisiä virhetyyppejä, joita esiintyy oppilaiden ratkaistessa muuttujia sisältäviä tehtäviä. Kiinnostuksen kohteena oli myös ohjauksen vaikutus oppilaiden kykyyn käsitellä muuttujia. Tut…