Manual operation simulation using motion-time analysis toward labor productivity estimation: A case study of concrete pouring operations

Running-time analysis of ant colony optimization (ACO) is crucial for understanding the power of the algorithm in computation. This paper conducts a running-time analysis of ant system algorithms (AS) as a kind of ACO for traveling salesman problems (TSP). The authors model the AS algorithm as an absorbing Markov chain through jointly representing the best-so-far solutions and pheromone matrix as a discrete stochastic status per iteration. The running-time of AS can be evaluated by the expected first-hitting time (FHT), the least number of iterations needed to attain the global optimal solution on average. The authors derive upper bounds of the expected FHT of two classical AS algorithms (i.e., ant quantity system and ant-cycle system) for TSP. They further take regular-polygon TSP (RTSP) as a case study and obtain numerical results by calculating six RTSP instances. The RTSP is a special but real-world TSP where the constraint of triangle inequality is stringently imposed. The numerical results derived from the comparison of the running time of the two AS algorithms verify our theoretical findings.

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Labor productivity of small-scale agriculture and its influence on agricultural landscape conservation in mountainous areas in China: a case study of rice farming in Hani terraced region

Environmental Science and Pollution Research ◽

10.1007/s11356-020-08815-z ◽

2020 ◽

Vol 27 (32) ◽

pp. 39795-39806 ◽

Cited By ~ 1

Author(s):

Yongxun Zhang ◽

Lulu He ◽

Longteng Liu ◽

Qingwen Min

Keyword(s):

Labor Productivity ◽

Agricultural Landscape ◽

Small Scale ◽

Landscape Conservation ◽

Rice Farming ◽

Mountainous Areas

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Using NDVI algorithm in Sentinel-2A imagery for rice productivity estimation (Case study: Compreng sub-district, Subang Regency, West Java)

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/481/1/012064 ◽

2020 ◽

Vol 481 ◽

pp. 012064

Author(s):

F Khoirunnisa ◽

Supriatna ◽

A Wibowo

Keyword(s):

West Java ◽

Rice Productivity ◽

Productivity Estimation ◽

Sentinel 2A

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Time analysis of throwing motions to second base by baseball catchers: Comparison of three throwing motions

International Journal of Sports Science & Coaching ◽

10.1177/1747954120930370 ◽

2020 ◽

Vol 15 (5-6) ◽

pp. 677-684

Author(s):

Koichi Kawabata ◽

Tatsuya Urata ◽

Koji Fukuda ◽

Satoru Tanabe

Keyword(s):

High Speed ◽

Time Analysis ◽

Release Times ◽

Motion Time ◽

Ball Velocity ◽

Positive Correlations ◽

Throwing Motion ◽

Motion Types

The purpose of this study was to investigate a baseball catcher’s throwing time to second base using three throwing motion types. The subjects were professional ( n = 4) and college ( n = 12) baseball catchers. Two high-speed cameras were set to capture the throwing motion, while one was set to capture the net on second base. The throwing time of quick throw (throwing motion to release the ball immediately after catching the ball rather than usual throwing motion) was significantly shorter than those of usual throw (throwing motion used during games and practice) and fast ball throw (throwing motion to increase the ball velocity than usual throwing motion). From this result, it became clear that quick throw is the optimal throwing motion when judged by time. Thus, with respect to correlations between variables, there were significant positive correlations between throwing and motion times (usual throw: r = 0.760; fast ball throw: r = 0.719; quick throw: r = 0.767), and between throwing and airborne times (usual throw: r = 0.784; fast ball throw: r = 0.744; quick throw: r = 0.806), for all three throwing motions. However, negative correlations were shown between throwing and release times in usual throw and fast ball throw. The results suggest that, to shorten the throwing time, it is necessary to shorten the hold and stride times and to improve the ability to throw the ball as fast as possible with a shorter motion time.

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