scholarly journals Multi-Product Forwarder-Based Timber Extraction

2020 ◽  
Vol 41 (2) ◽  
pp. 231-242
Author(s):  
Kayla Gagliardi ◽  
Simon Ackerman ◽  
Pierre Ackerman
Keyword(s):  
Fuel Consumption ◽  
System Productivity ◽  
Product Assortment ◽  
Productivity Data ◽  
Machine Productivity ◽  
Load Volume ◽  
Industrial Plantation ◽  
African Context ◽  
Multiple Variables ◽  
Load Size

Accurate predictions in forest operations can be used towards effective planning, costing, and maximizing the productivity of machines in mechanised cut-to-length (CTL) harvesting. There is a general and substantial gap in forwarder productivity data available for pine sawtimber in South Africa at present, and as the number of product assortments being harvested increase there is a need for more work to quantify the effects of extracting products of different dimensions. The aim of this study was to calculate the time consumption and productivity of two models of Ponsse forwarders (15 t and 20 t capacity) to consider and compare the effects of multiple variables including machine capabilities, product assortment, load size, extraction distance and fuel consumption. Productivity averaged at 34.08 m3 per productive machine hour excluding delays longer than one minute (PMH1) for the smaller machine, and 55.94 m3/PMH1 for the larger machine. Productivity and average log volume were strongly positively correlated. Regression models were created for each machine where load volume and extraction distance were both significant factors for predicting productivity. Average fuel consumption of the smaller machine was 15.55 l/PMH1 and 0.47 l/m3, and 20.57 l/PMH1 and 0.43 l/m3 for the larger machine. The product with the largest volume was found to require the least fuel per m3. The models developed could aid in predicting system productivity and potentially carbon emissions under similar conditions in a South African context of industrial plantation forestry.

Regression analysis using auxiliary information from time studies of cable yarding operations

1989 ◽  
Vol 19 (10) ◽  
pp. 1262-1266 ◽  
Author(s):  
Andrew F. Howard ◽  
Guillaume Thérien
Keyword(s):  
Linear Regression ◽  
Multiple Linear Regression ◽  
Auxiliary Information ◽  
Statistical Efficiency ◽  
System Productivity ◽  
Mixed Estimator ◽  
Load Volume ◽  
Cable Yarding ◽  
Load Size ◽  
Two Alternatives

Time studies are commonly employed in the analysis of cable yarding productivity. For a given site and system, productivity is a function of the yarding distance and the load size. Field conditions make it more difficult to sample load volume than yarding distance, which leads to substantial differences in sample size for the two variables. When multiple linear regression is used to fit equations for predicting yarding productivity to these data, many of the observations must be omitted. Two alternatives to conventional multiple linear regression that make use of the auxiliary information in the additional observations on yarding distance were compared on the basis of statistical efficiency. A mixed estimator was found to be most efficient for all yarding systems studied.

scholarly journals Insight into the Productivity, Cost and Soil Impacts of Cable-assisted Harvester-forwarder Thinning in Western Oregon

2019 ◽  
Vol 66 (1) ◽  
pp. 82-96 ◽  
Author(s):  
Preston Q Green ◽  
Woodam Chung ◽  
Ben Leshchinsky ◽  
Francisca Belart ◽  
John Sessions ◽  
...  
Keyword(s):  
Pacific Northwest ◽  
Soil Compaction ◽  
The United States ◽  
Soil Conditions ◽  
Productivity Cost ◽  
System Productivity ◽  
Machine Productivity ◽  
Before And After ◽  
Harvesting Systems ◽  
Soil Measurements

Abstract Cable-assisted (or tethered) mechanized harvesting has recently been introduced to the Pacific Northwest of the United States, and is rapidly being adopted by the forest industry. However, potential environmental impacts, productivity and cost of the new harvesting systems have not been well-assessed. This study aims to examine the effects of cable assistance on soil compaction, system productivity and cost through a field-based experiment. A harvester-forwarder system was used to thin a harvest unit on dry soils in western Oregon, with and without cable-assistance. We conducted a detailed time study during operations and collected soil measurements before and after machine passes. Machine productivity ranged from 28.75 to 92.36 m3 per scheduled machine hour, with resulting unit costs for untethered and tethered systems ranging from $13.19 to $18.13/m3. Our results showed reduced soil impacts in both extent and degree of soil compaction when cable assistance was employed. The reduced extent of soil impacts is attributed to a reduction in track wander owing to the operative tensions of the tether cable, and the smaller increase in soil density appears to be attributed to combined effects of initially denser soil conditions and reduced shear displacement as a result of cable-assistance.

scholarly journals Ground-Based Extraction on Salvage Logging in Two High Forests: A Productivity and Cost Analysis

Forests ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 729 ◽  
Author(s):  
Afraz Iranparast Bodaghi ◽  
Mehrdad Nikooy ◽  
Ramin Naghdi ◽  
Rachele Venanzi ◽  
Francesco Latterini ◽  
...  
Keyword(s):  
Work Productivity ◽  
System Productivity ◽  
Salvage Logging ◽  
Forest Logging ◽  
Standing Trees ◽  
Load Volume ◽  
Effective Cost ◽  
Work Planning ◽  
The Cost ◽  
Harvesting Costs

Working time studies, work productivity, and cost assessments of forest logging are of interest to forest managers and planners. These aspects are particularly important in salvage logging, because of difficulties due to irregularly positioned fallen trees in forest areas, and due to particular aspects related to the absence of work planning. In this research, system productivity and the cost of salvage logging are analyzed for two mountain forests managed with close-to nature-silviculture: the Hyrcanian forest, using extraction by a skidder, and the Camaldoli forest, using extraction by tractors. The system productivity of salvage logging by skidders and tractors was calculated as 1.54 and 0.81 m3·h−1, respectively. In contrast to common logging, system productivity was about 6- to 15-fold lower in salvage logging. The effective cost consumptions for the skidder and tractor were calculated as $72.57 and $118.62 USD·m−3, respectively. For both yards, winching time increased due to increasing winching distance and winching load volume. The same result was determined for skidding time in relation to load volume and distance. The possible cost decreases for the skidder and tractor were calculated as 2.6% and 4.3%, respectively. The results revealed that operational costs for extracting wind-fallen trees are higher than for traditional standing-trees extraction for both situations studied. In both cases, the harvesting costs were higher than the timber price by 10% to 30%. Therefore, extraction of wind-fallen trees has no economic justification in these forests.

scholarly journals MANAJEMEN PENGELOLAAN TAMBAK IKAN BANDENG DESA LABUHAN KURIS KECAMATAN LAPE KABUPATEN SUMBAWA

2020 ◽  
Vol 8 (1) ◽  
pp. 93-104
Author(s):  
Muhammad Kadafi Prawiro ◽  
Arif Budi Witarto
Keyword(s):  
Sampling Technique ◽  
P Value ◽  
Productivity Level ◽  
System Productivity ◽  
Traditional System ◽  
Productivity Data ◽  
Significant Difference ◽  
Management Technology ◽  
The Difference ◽  
Intensive System

Many pond farmers cultivate milkfish by using traditional and semi-intensive system, whereas the difference of system used will generate the difference of farmer's revenue. The aim of this research is to know the comparison of milkfish pond's productivity level by traditional and semi-intensive system in Labuhan Kuris, Lape subdistrict. Sampling technique applies Purpose Sampling method and data analysis method be used is Mann-Whimey U-test. The result of average test of milkfish pond's productivity data within traditional and semi-intensive system gets p value < 0.05 means that there is significant difference between productivity data, where intensive system productivity is higher than traditional system. The result of average test of milkfish pond's yields data within traditional and semi-intensive system gets p value < 0.05 means that there is significant difference between yields data, where the yields of intensive system is greater than traditional system. Keywords: The Characteristics Of Milkfish, Milkfish, Management Technology, Income and  Productivity

scholarly journals Reviewing productivity studies of skidders working in coniferous forests and plantations

2020 ◽  
Vol 21 (2) ◽  
pp. 83-98
Author(s):  
Mohammad Reza Ghaffariyan
Keyword(s):  
Coniferous Forests ◽  
Native Forest ◽  
Operation Conditions ◽  
Volume Load ◽  
Machine Productivity ◽  
Different Types ◽  
Load Volume ◽  
Type Size ◽  
Clear Fell ◽  
Vari Ations

Skidding is an important element of harvesting operations, which contributes to the extraction of wood. A skidder can be used in different types of harvesting operations, such as thinning, clear fell, native forest thinning or salvage work. The main goal of this article was to review the available stud-ies on productivity of skidding operations in coniferous forests/ plantations. Information on skid-der productivity was collected from publications and then was classified in three regions, including North America, Europe and the Southern Hemisphere. The parameters affecting machine productivity included machine type/ size, tree volume/ log volume/ load volume, average skidding distance and slope of the ground for each reported productivity. The average productivity reported in the published reports ranged from 9.3 m3/PMH to 78.0 m3/PMH. Detailed information and conclusions collected from various studies can be of use to forest academic and industry users to gain knowledge about vari-ations of skidder productivity in different regions and site/ operation conditions, which can be helpful for predicting, controlling and improving current levels of productivity.&nbsp;

Accuracy of Four Language Analysis Procedures Performed Automatically

2001 ◽  
Vol 10 (2) ◽  
pp. 180-188 ◽  
Author(s):  
Steven H. Long ◽  
Ron W. Channell
Keyword(s):  
Automatic Identification ◽  
Published Data ◽  
Typically Developing ◽  
Language Impaired ◽  
Productivity Data ◽  
Language Analysis ◽  
Word Classes ◽  
Human Coder ◽  
Impaired Children ◽  
Metalinguistic Skills

Most software for language analysis has relied on an interaction between the metalinguistic skills of a human coder and the calculating ability of the machine to produce reliable results. However, probabilistic parsing algorithms are now capable of highly accurate and completely automatic identification of grammatical word classes. The program Computerized Profiling combines a probabilistic parser with modules customized to produce four clinical grammatical analyses: MLU, LARSP, IPSyn, and DSS. The accuracy of these analyses was assessed on 69 language samples from typically developing, speech-impaired, and language-impaired children, 2 years 6 months to 7 years 10 months. Values obtained with human coding and by the software alone were compared. Results for all four analyses produced automatically were comparable to published data on the manual interrater reliability of these procedures. Clinical decisions based on cutoff scores and productivity data were little affected by the use of automatic rather than human-generated analyses. These findings bode well for future clinical and research use of automatic language analysis software.

Abusive Men's Use of Children to Control Their Partners and Ex-Partners

2007 ◽  
Vol 12 (1) ◽  
pp. 54-61 ◽  
Author(s):  
Marisa L. Beeble ◽  
Deborah Bybee ◽  
Cris M. Sullivan
Keyword(s):  
United States ◽  
Intimate Partner Violence ◽  
Partner Violence ◽  
Emotional Abuse ◽  
The United States ◽  
Intimate Partner ◽  
Anecdotal Evidence ◽  
Multiple Variables ◽  
The Relationship

While research has found that millions of children in the United States are exposed to their mothers being battered, and that many are themselves abused as well, little is known about the ways in which children are used by abusers to manipulate or harm their mothers. Anecdotal evidence suggests that perpetrators use children in a variety of ways to control and harm women; however, no studies to date have empirically examined the extent of this occurring. Therefore, the current study examined the extent to which survivors of abuse experienced this, as well as the conditions under which it occurred. Interviews were conducted with 156 women who had experienced recent intimate partner violence. Each of these women had at least one child between the ages of 5 and 12. Most women (88%) reported that their assailants had used their children against them in varying ways. Multiple variables were found to be related to this occurring, including the relationship between the assailant and the children, the extent of physical and emotional abuse used by the abuser against the woman, and the assailant's court-ordered visitation status. Findings point toward the complex situational conditions by which assailants use the children of their partners or ex-partners to continue the abuse, and the need for a great deal more research in this area.

Workload Perception of Air Traffic Control Officers and Pilots During Continuous Descent Operations Approach Procedures

2019 ◽  
Vol 9 (1) ◽  
pp. 2-11
Author(s):  
Marina Efthymiou ◽  
Frank Fichert ◽  
Olaf Lantzsch
Keyword(s):  
Fuel Consumption ◽  
Traffic Control ◽  
Air Traffic Control ◽  
Negative Impact ◽  
Air Traffic ◽  
Reduce Fuel Consumption ◽  
Total Load ◽  
Open Path

Abstract. The paper examines the workload perceived by air traffic control officers (ATCOs) and pilots during continuous descent operations (CDOs), applying closed- and open-path procedures. CDOs reduce fuel consumption and noise emissions. Therefore, they are supported by airports as well as airlines. However, their use often depends on pilots asking for CDOs and controllers giving approval and directions. An adapted NASA Total Load Index (TLX) was used to measure the workload perception of ATCOs and pilots when applying CDOs at selected European airports. The main finding is that ATCOs’ workload increased when giving both closed- and open-path CDOs, which may have a negative impact on their willingness to apply CDOs. The main problem reported by pilots was insufficient distance-to-go information provided by ATCOs. The workload change is important when considering the use of CDOs.

Exploring recidivism in the South African context.

1998 ◽  
Author(s):  
Belinda Bedell ◽  
Nicholas Challis ◽  
Charl Cilliers ◽  
Joy Cole ◽  
Wendy Corry ◽  
...  
Keyword(s):  
South African ◽  
South African Context ◽  
The South ◽  
African Context
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