scholarly journals Evaluation of forest inventory processes in a forest under concession in the southwestern Brazilian Amazon

2019 ◽  
Vol 49 (2) ◽  
pp. 91-96
Author(s):  
Felipe KAUAI ◽  
Ana Paula Dalla CORTE ◽  
Vinicius CYSNEIROS ◽  
Allan Libanio PELISSARI ◽  
Carlos Roberto SANQUETTA
Keyword(s):  
Forest Inventory ◽  
Random Sampling ◽  
Basal Area ◽  
Stand Density ◽  
Simple Random Sampling ◽  
Relevant Information ◽  
Cluster Sampling ◽  
Two Stage ◽  
Wood Volume ◽  
Management Plans

ABSTRACT Forest inventory procedures are of utmost importance to studies of wood volume stocks, and forest structure and diversity, which provide relevant information to public policies, management plans and ecological research. The present work focused on the performance of inventory techniques in the Amazon region to evaluate wood volume stocks with higher levels of accuracy while maintaining sampling intensity fixed. Two sampling processes were assessed: simple random sampling and two-stage cluster sampling. The processes were evaluated through the allocation of sampling units with different dimensions, and the effectiveness of the generated estimators was analyzed as a function of stand density and basal area. Simple random sampling resulted in the smallest errors, reaching 9% when all species were sampled together. The method depicted forest phytosociological parameters with greater sensitivity, whereas two-stage cluster sampling produced the least accurate estimators and presented slower responses to variation in phytosociological parameters.

scholarly journals SISTEMA DE INVENTÁRIO FLORESTAL PARA SERINGAL NATIVO

FLORESTA ◽  
2002 ◽  
Vol 32 (1) ◽  
Author(s):  
José de Arimatéa Silva ◽  
Sylvio Péllico Netto
Keyword(s):  
Forest Inventory ◽  
Random Sampling ◽  
Rubber Tree ◽  
Basal Area ◽  
Simple Random Sampling ◽  
Inventory System ◽  
Stratified Random Sampling ◽  
Stage Number ◽  
Second Stage ◽  
Two Stages

Este trabalho teve como objetivo desenvolver um Sistema de Inventário Florestal para seringal nativo. Aplicou-se a Amostragem Inteiramente Aleatória (AIA), em dois estágios: colocação de seringa, no primeiro, e estrada de seringa, no segundo. Foram estimados: número de seringueiras por estrada (N), área basal das seringueiras da estrada (G) e volume da porção explorada do fuste (V). Realizou-se uma pós-estratificação, considerando-se estradas de centro e de margem, aplicando-se a Amostragem Estratificada (AE). Comparou-se a AIA com a AE, com base na eficiência relativa. Os resultados revelaram as seguintes estimativas para as médias estratificadas: N=100; G=19,00 m², V= 62,8 m³. Concluiu-se que a AE revelou-se mais eficiente que a AIA para estimar as variáveis analisadas. Propõe-se que um sistema de inventário para seringal nativo deve combinar: informações de um censo das colocações; um processo de amostragem estratificada; e um método de amostragem cuja unidade de amostra é a estrada de seringa. Forest Inventory System for Rubber Trees Abstract Forest Inventory System for rubber trees. This work had as objective to develop an Inventory System for native rubber tree areas. The Simple Random Sampling (SRS) was applied in two stages: the setting, in the first, and the rubber trees tracks, in the second stage. Number of rubber trees per track (N), basal area of the rubber trees track (G) and volume of the stem portion explored (V) were the parameters estimated. A post-stratification was become fulfilled, considering itself center tracks and river side tracks, applying itself it Stratified Random Sampling (STRS). It was compared SRS with the STRS, on the basis of the relative efficiency. The results showed the following estimates for the stratified means: N=100; G=19,00 m², V = 62,8 m³. It was concluded that the STRS showed more efficient than the SRS to estimate the analyzed variables. It is considered that an Inventory System for native rubber tree areas must match: information of a census of the settings; a process of Stratified Random Sampling; and a sampling method whose unit of sample is the rubber tree track.

Potential for wider application of 3P sampling in forest inventory

2011 ◽  
Vol 41 (7) ◽  
pp. 1500-1508 ◽  
Author(s):  
P.W. West
Keyword(s):  
Forest Inventory ◽  
Random Sampling ◽  
Simple Random Sampling ◽  
Auxiliary Variable ◽  
Mathematical Approach ◽  
Wood Volume ◽  
Stem Wood ◽  
Timber Sales ◽  
Tree Stem ◽  
Small Forest

Sampling with probability proportional to prediction (3P sampling) is useful where the variable of interest to a forest inventory is costly to measure and where there exists a cheaper to measure auxiliary variable, which correlates positively with the variable of interest. Two forms of 3P sampling, termed “classical” and “point-” 3P sampling, have received some use in forest inventory. However, both have limitations that have restricted their use mainly to estimation of tree stem wood volume for timber sales over small forest areas in North America. A more general form of 3P sampling, termed here “ordinary” 3P sampling, has been all but ignored to date. It has potential for use in inventory of a broad range of forest attributes, both floral and faunal and both commercial and environmental, across large or small forest areas. Using a common mathematical approach, the present work derives the estimators of the population mean for these three forms of 3P sampling. Their properties are compared with simple random sampling through Monte Carlo simulations based on two example forest populations. The work lays a basis from which 3P sampling might develop further and enjoy wider application in forest inventory than has been the case previously.

Die antizipierte Varianz: ein Werkzeug für die Optimierung von Waldinventuren | The anticipated variance: a tool for the optimization of forest inventory

2003 ◽  
Vol 154 (3-4) ◽  
pp. 117-121 ◽  
Author(s):  
Daniel Mandallaz
Keyword(s):  
Spatial Distribution ◽  
Forest Inventory ◽  
Random Sampling ◽  
Poisson Model ◽  
Simple Algebra ◽  
Simple Random Sampling ◽  
Two Stage ◽  
Two Phase ◽  
Forest Inventories ◽  
Mathematical Review

This paper gives a non-mathematical review of the concept of anticipated variance which allows to solve entirely the optimisation problem for two-phase two-stage forest inventories with cluster or simple random sampling, in the sense that the anticipated variance is minimised for given costs. The anticipated variance is the average of the design-based variance under a local Poisson-model for the spatial distribution of the trees. The resulting sampling rules have a clear intuitive background and require only simple algebra to be implemented. The required parameters can be estimated from any pre-existing two-phase inventory. An example based on the Swiss National Inventory illustrates the method.

scholarly journals Two stage adaptive cluster sampling based on ordered statistics

2019 ◽  
Vol 16 (1) ◽  
Author(s):  
Girish Chandra ◽  
Neeraj Tiwari ◽  
Raman Nautiyal
Keyword(s):  
Random Sampling ◽  
Real Life ◽  
Simple Random Sampling ◽  
The Other ◽  
Cluster Sampling ◽  
Adaptive Cluster Sampling ◽  
Two Stage ◽  
Life Data ◽  
Real Life Data ◽  
Ordered Statistics

The estimation problem on sparsely distributed populations using adaptive cluster sampling (ACS) is discussed. In the first phase of ACS, two stage sampling is used in which primary and secondary sampling units are selected using simple random sampling without replacement. The idea of Thompson (1996) is introduced in order to choose an appropriate fixed value of pre-specified condition, which might represent the number of rare species, before conducting the survey by the use of order statistics. Different estimators of the population mean under the two possible schemes (open and closed boundaries of primary sampling units) are studied and the Rao-Blackwell theorem for improving these estimators is also used. Numerical illustrations, one on real life data and the other based on simulation study, are discussed for these two schemes. This design may be quite useful in environmental, forestry and other areas of research dealing with rare, endangered or threatened species.

scholarly journals PENGARUH IMPLEMENTASI KEBIJAKAN PERIMBANGAN KEUANGAN TERHADAP KUALITAS PELAYANAN PUSKESMAS: STUDI KASUS KOTA BANJAR PROPINSI JAWA BARAT

2010 ◽  
Vol 12 (1) ◽  
pp. 25
Author(s):  
M. Arry Djauhari
Keyword(s):  
Random Sampling ◽  
Simple Random Sampling ◽  
Structure Equation ◽  
Equation Modeling ◽  
Cluster Sampling ◽  
Structure Equation Modeling

Pemerintah Kota Banjar dalam memberikan pelayanan kesehatan masih tergantung kepada kebijakan perimbangan keuangan, karena terbatasnya sumberdaya yang di miliki. Implementasi kebijakan perimbangan keuangan yang belum optimal dengan indikasi terbatasnya kemampuan sumberdaya manusia, baik secara kualitas maupun kuantitas yang memperlihatkan kecenderungan pengaruh yang terbesar dalam dimensi implementasi kebijakan. Keterbatasan kemampuan dalam mengelola sumber daya baik sumberdaya alam maupun sumberdaya manusia sangat tergantung kepada kemampuan keuangan daerah sendiri dalam pembiayaan penyelenggaraan otonomi daerahnya. Metode penelitian yang digunakan dalam penelitian ini adalah metode eksplanasi, dengan sample gugus bertahap (Cluster sampling), pengambilan sampel dilakukan secara bertahap berdasarkan wilayah-wilayah administratif yang terdapat pusat pelayanan kesehatan dengan metode acak sederhana (Simple Random Sampling). Pengolahan data diuji dengan menggunakan Structure Equation Modeling (SEM) dengan suatu prosedur yang di dasarkan pada Methods of Succesive Interval. Hasil penelitian menunjukkan bahwa implementasi kebijakan perimbangan keuangan dalam pelaksanaan otonomi daerah yang didasarkan pada dimensi komunikasi, sumberdaya, disposisi/sikap pelaksana dan struktur birokrasi secara bersama-sama atau tersendiri secara signifikan mempengaruhi kualitas pelayanan kesehatan. Dimensi dukungan merupakan dimensi yang paling besar pengaruhnya terhadap peningkatan pelayanan kesehatan diikuti dengan struktur birokrasi, sumberdaya dan komunikasi.

scholarly journals ANALISA KELAYAKAN USAHATANI JAGUNG DI KABUPATEN CIAMIS

2017 ◽  
Vol 1 (2) ◽  
pp. 139
Author(s):  
Ai Husnul Khotimah
Keyword(s):  
Random Sampling ◽  
Simple Random Sampling ◽  
Two Stage ◽  
Cluster Random Sampling

Penelitian ini bertujuan untuk mengetahui: (1) Besarnya biaya dan penerimaan pada usahatani jagung di Kabupaten Ciamis (2) R/C ratio pada usahatani jagung. Metode yang digunakan dalam penelitian ini adalah metode survai dengan mengambil kasus pada komoditi jagung di Kabupaten Ciamis. Teknik penarikan sampel dilaksanakan menggunakan two stage cluster random sampling untuk sampel area dan strata simple random sampling untuk sampel petani. Data yang diperoleh dianalisa secara deskriptif. Usahatani jagung dianalisis dengan analisis biaya, pendapatan dan R/C. Hasil penelitian menunjukkan bahwa usahatani jagung di Kabupaten Ciamis sudah mulai pada usahatani komersial, dengan teknik budidaya yang masih konvensional, yang pelaksanaannya dipadukan dengan budidaya ternak. R/C yang didapat sebesar 2,22 menunjukkan bahwa usahatani jagung di Kabupaten Ciamis menguntungkan.

scholarly journals Analisi Kinerja Harga Pengaruhnya Terhadap Reputasi dan Keputusan Menggunakan Jasa Penerbangan (Survei terhadap penumpang Air Asia dengan rute Bandung – Denpasar)

2018 ◽  
Vol 5 (2) ◽  
Author(s):  
Anisa Rosdiana
Keyword(s):  
Random Sampling ◽  
Simple Random Sampling ◽  
Cluster Sampling ◽  
Data Path

Penumpang memiliki peran sentral selaku pembuat keputusan untuk menggunakan maskapai penerbangan. Namun pertumbuhan jumlah penumpang Air Asia mengalami penurunan. Hal ini terjadi karena reputasi Air Asia yang kurang baik. Melalui upaya kinerja harga, diharapkan dapat meningkatkan jumlah pertumbuhan penumpang Air Asia.Adapun tujuan dari penelitian ini adalah untuk mengetahui: (1) gambaran kinerja harga pada penumpang maskapai penerbangan Air Asia (2) gambaran reputasi Air Asia pada penumpang maskapai penerbangan Air Asia (3) gambaran keputusan menggunakan pada penumpang maskapai penerbangan Air Asia (4) pengaruh kinerja harga terhadap reputasi dan keputusan menggunakan masakapai penerbanganAir Asia.Objek dari penelitian ini adalah penumpang Air Asia dengan rute Bandung – Denpasar, adapun metode penelitiannya menggunakan deskriftif dan verifikatif. Sumber data yang dipergunakan adalah primer dan sekunder. Populasi sebanyak 214.450 orang diambil sample penelitian sejumlah 100 orang. Simple Random Sampling khususnya Cluster Sampling merupakan teknik pengambilan sample yang penulis pilih. Teknik pengumpulan data dilakukan melalui wawancara, observasi, kuesioner, dan studi literatur. Untuk mengukur besarnya pengaruh kinerja harga terhadap reputasi dan keputusan menggunakan maskapai penerbangan, digunakan teknik analisis data path (analisis jalur). Hasil penelitian mengungkapkan bahwa pelaksanaan kinerja harga dinilai oleh penumpang cukup tinggi. Reputasi dinilai cukup tinggi, sedangkan keadaan keputusan menggunakan maskapai penerbangan secara umum dinilai cukup tinggi. Besarnya pengaruh kinerja harga terhadap reputasi adalah cukup tinggi sebesar 60,8%. Besarnya pengaruh kinerja harga terhadap keputusan menggunakan maskapai penerbangan adalah cukup tinggi sebesar 75,8%. Besarnya pengaruh reputasi terhadap keputusan menggunakan maskapai penerbangan adalah cukup tinggi sebesar 69,3%. Sedangkan pengaruh kinerja harga terhadap reputasi dan keputusan menggunakan maskapai penerbangan berpengaruh secara simultan signifikan. Hasil penelitian, maka perlu diadakannya usaha dalam peningkatan kinerja harga yang sesuai dengan harapan penumpang termasuk dalam kualitas pelayanan agar dapat meningkatkan reputasi perusahaan sehingga penumpang memutuskan untuk menggunakan maskapai penerbangan Air Asia

PARENTAL SOCIO-ECONOMIC BACKGROUND AND STUDENTS’ ACADEMIC PERFORMANCE IN PUBLIC SECONDARY SCHOOLS IN IKOLOMANI SUB- COUNTY, KAKAMEGA COUNTY, KENYA

2019 ◽  
Vol 3 (1) ◽  
pp. 15
Author(s):  
Brenda Muhavi Madegwa ◽  
Sr. Dr. Elizabeth Piliyesi ◽  
Sr. Dr. Theonestina Katundano
Keyword(s):  
Academic Performance ◽  
Secondary Schools ◽  
Random Sampling ◽  
Quantitative Data ◽  
Simple Random Sampling ◽  
Cluster Sampling ◽  
Parental Occupation ◽  
Quantitative And Qualitative Research ◽  
Economic Background ◽  
Parental Level

Purpose: The purpose of this study was to investigate to what extent the socio- economic background of parents influence the academic performance of students in public secondary schools in Ikolomani Sub- County, Kakamega County. This study was guided by the following research questions: How does parental level of education influence students’ performance? How does parental occupation level influence students’ performance? How does parental income level influence students’performance? What are the socioeconomic challenges facing parents in enhancing students’ academic performance in public secondary schools in lkolomani Sub-County? What are the possible solutions to enhance students’ academic performance in public secondary schools in lkolomani Sub-County?Methodology: The study used both quantitative and qualitative research approaches. The study employed proportionate stratified random sampling to select the schools while purposive, cluster sampling and simple random sampling was used to select the students. Teachers were selected using stratified and simple random sampling. Principals, parents’ representatives and Education officer were purposively selected. Data were collected using questionnaires, document analysis and interview guide. Qualitative and quantitative data were concurrently collected and analyzed. Statistical package for Social Science (SPSS version 23) was used to analyze quantitative data while qualitative data was analyzed thematically to obtain views and perceptions of the respondents.Results: The study found that parental socio-economic background played  a key role in enhancement of students’ academic performance.Recommendations: The study recommended that parents should be encouraged to start small income generating business so as to cater for the educational needs of their children.

Forest inventory estimation with mapped plots

2004 ◽  
Vol 34 (2) ◽  
pp. 493-497 ◽  
Author(s):  
Paul C Van Deusen
Keyword(s):  
Forest Inventory ◽  
Random Sampling ◽  
Simple Random Sampling ◽  
Mean Squared Errors ◽  
Additional Work ◽  
Fixed Area ◽  
Plot Design

Procedures are developed for estimating means and variances with a mapped-plot design. The focus is on fixed-area plots, and simulations are used to validate the proposed estimators. The mapped-plot estimators for means and variances are compared with simple random sampling estimators that utilize only full plots. As expected, the mapped-plot estimates have smaller mean squared errors than the simple random sampling estimates. The theory for fixed-area plots is easy to apply, although additional work is required to map plots in the field. Corresponding theory for variable plots is developed but not tested with simulations. The difficulty of applying these methods to variable plots is greater, but not prohibitive.

A Test of Cluster Sampling in Forest Inventories

1975 ◽  
Vol 5 (2) ◽  
pp. 269-272 ◽  
Author(s):  
G. M. Bonnor
Keyword(s):  
Random Sampling ◽  
Sampling Design ◽  
Simple Random Sampling ◽  
Cluster Sampling ◽  
Field Sampling ◽  
Forest Inventories ◽  
Straight Line ◽  
Time Required ◽  
Variance Estimates ◽  
The Given

During a recent pilot survey in Newfoundland, forest data were collected using a stratified, one-stage cluster-sampling design. The data were analyzed to determine if, within the stratified framework, cluster sampling would be more efficient than simple random sampling. Each cluster consisted of five point-samples located in a straight line. For the analysis, volume and variance estimates were determined from clusters of 1,2,3,4 and 5 points. During the survey, records were kept of the time required to complete various field-sampling tasks. These were used in lieu of cost data in the analysis. Results indicated that, for the given conditions, simple random sampling was more efficient than cluster sampling. However, relatively small changes in the conditions would make cluster sampling more efficient.

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