Transactions Hong Kong Institution of Engineers最新文献_第5页

Short-term electricity grid maximum demand forecasting with the ARIMAX-SVR Machine Learning Hybrid Model 基于ARIMAX-SVR机器学习混合模型的短期电网最大需求预测

Transactions Hong Kong Institution of Engineers Pub Date : 2021-04-15 DOI: 10.33430/V28N1THIE-2020-0005

H. F. Chow

{"title":"Short-term electricity grid maximum demand forecasting with the ARIMAX-SVR Machine Learning Hybrid Model","authors":"H. F. Chow","doi":"10.33430/V28N1THIE-2020-0005","DOIUrl":"https://doi.org/10.33430/V28N1THIE-2020-0005","url":null,"abstract":"This paper proposes and discusses the viability of a short-term grid maximum demand forecasting model combining autoregressive integrated moving average with regressors (ARIMAX) and support vector regression (SVR). Grid demand forecasting is essential to generation unit scheduling, maintenance planning and system security. Traditionally, grid demand is forecasted using multivariate linear regression models with parameters adjusted to past data. A disadvantage of the linear regression model is that the parameters require regular adjustment, otherwise the prediction accuracy will deteriorate over time. With recent advances in the field of machine learning and lower computational costs, the usage of machine learning in the power industry becomes increasingly practicable. The proposed model is a machine learning model that combines ARIMAX and SVR to exploit their respective effectiveness in predicting linear and non-linear data. In contrast to linear regression models, the machine learning model automatically updates itself when new data is included. The hybrid model is benchmarked against other forecasting models and demonstrated a marked improvement in accuracy, achieving RMSE of 67.7MW and MAPE of 1.32% in a seven-day forecast.","PeriodicalId":35587,"journal":{"name":"Transactions Hong Kong Institution of Engineers","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45539913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Development of prototype machine brake and car safety gear testers for traction lift systems 牵引提升系统原型机制动器和汽车安全装置测试仪的开发

Transactions Hong Kong Institution of Engineers Pub Date : 2021-04-15 DOI: 10.33430/V28N1THIE-2020-0044

A. So, K. Lam, A. C. T. Kong, Jeff H. Tse

{"title":"Development of prototype machine brake and car safety gear testers for traction lift systems","authors":"A. So, K. Lam, A. C. T. Kong, Jeff H. Tse","doi":"10.33430/V28N1THIE-2020-0044","DOIUrl":"https://doi.org/10.33430/V28N1THIE-2020-0044","url":null,"abstract":"Machine brakes and safety gears of traction lifts are two critical components of the biggest safety concerns, as the main braking system and redundant fail-safe mechanism respectively stop and hold lift cars from unintended car movement, overspeed or under a free-fall condition during emergency. There are challenges of routine maintenance on how to continually verify the effectiveness of them to mitigate risk potentials of equipment failure. This pilot study intends to design, implement and test low-cost, non-intrusive and on-line prototype testers with the aid of sensors for real-time monitoring of critical parameters of these safety devices. Critical parameters that are measurable include real-time variations of brake lining temperature, brake solenoid current, vibrational patterns of brake arms and lift car, position of lift car, and the actuating status of safety gears. Critical parameters after processing include a newly defined energy of brake arm operation and estimated deceleration rate of a fully loaded car by safety gears operation on an unloaded car. Early signs of abnormalities of these two safety devices can be detected before they fail. Additionally, the prototype testers can facilitate more frequent unloaded full-speed testing of safety gears to verify the effectiveness. The proof-of-concept prototype could be a quick monitoring alternative to existing and new traction lift systems.","PeriodicalId":35587,"journal":{"name":"Transactions Hong Kong Institution of Engineers","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44175106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Using market mechanism to stimulate sustainable use of the non-renewable environmental resource (groundwater) in Barind Tract of Bangladesh 利用市场机制刺激孟加拉国巴林德地区不可再生环境资源(地下水)的可持续利用

Transactions Hong Kong Institution of Engineers Pub Date : 2021-04-15 DOI: 10.33430/V28N1THIE-2020-0036

Anutosh Das, S. Kashem, M. Hasan

{"title":"Using market mechanism to stimulate sustainable use of the non-renewable environmental resource (groundwater) in Barind Tract of Bangladesh","authors":"Anutosh Das, S. Kashem, M. Hasan","doi":"10.33430/V28N1THIE-2020-0036","DOIUrl":"https://doi.org/10.33430/V28N1THIE-2020-0036","url":null,"abstract":"Agriculture, the main economic driver of Barind Tract, is highly dependent on groundwater for surface water paucity in the area. Notwithstanding, farmers use water capriciously due to its low price that makes a substantial drop in the water table. In this context, the research attempts to determine a market-based water pricing mechanism to encourage an optimal use of the scarce non-renewable resource. Required data was collected by questionnaire survey, Focus Group Discussion (FGD), Contingent Valuation Method, expert-opinion survey and subsequent literature works. The results reveal that depletion level has arrived at 20, 11, 7.5 feet in high, mid and low tract respectively over the last 22 years, which results in a number of economic-environmental externalities in the area. The research monetarily evaluated the cost of externalities and incorporated it with the marginal cost of extraction to increase efficiency of an existing pricing system. Regarding human reaction to price elasticity, the new price can be a reliable attempt to reduce an overconsumption pattern of water. Quantity of consumed water can be reduced to 14190.4 m3, 17759.59 m3 and 38510.6 m3 in a year in high, mid and low tract area respectively with its implementation. The research will serve as an initiative to conserve the valuable groundwater resource for future generations by managing consumer practice.","PeriodicalId":35587,"journal":{"name":"Transactions Hong Kong Institution of Engineers","volume":"28 1","pages":"39-48"},"PeriodicalIF":0.0,"publicationDate":"2021-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48344989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Plantar fascia loading at different running speed: a dynamic finite element model prediction 不同运行速度下足底筋膜负荷的动态有限元模型预测

Transactions Hong Kong Institution of Engineers Pub Date : 2021-04-15 DOI: 10.33430/V28N1THIE-2020-0011

T. L. Chen, D. Wong, Yan Wang, Ming Zhang

{"title":"Plantar fascia loading at different running speed: a dynamic finite element model prediction","authors":"T. L. Chen, D. Wong, Yan Wang, Ming Zhang","doi":"10.33430/V28N1THIE-2020-0011","DOIUrl":"https://doi.org/10.33430/V28N1THIE-2020-0011","url":null,"abstract":"Loads on the plantar fascia could be influenced by running speed and relate to its pathology. This study calculated and compared plantar fascia strains under different running speed conditions using a dynamic finite element foot model and computational simulations. The model was previously validated featuring twenty bones, bulk soft tissue, muscles/ligaments, and a solid part of plantar fascia. A runner performed running trials under one preferred speed (PS), two lower (PS - 10% and PS - 20%) and two higher (PS + 10% and PS + 20%) speed conditions. The movement data were processed to drive musculoskeletal modelling and calculated boundary/loading conditions for the subsequent finite element analyses. The results show that peak strains of the plantar fascia increased with increasing running speed. From PS – 20% to PS + 20%, peak strain in the proximal and distal fascia regions increased by 96.78% and 58.89% respectively. Running speed could directly affect plantar fascia loading, which should be considered in running regimens and rehabilitation programmes. However, prescribing speed control for runners is worth pondering as it influences the trade-off between maximum single-step loads and loading frequency, which in coalescence determine the risk of plantar fascia injury and warranted further investigations.","PeriodicalId":35587,"journal":{"name":"Transactions Hong Kong Institution of Engineers","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46324496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Are super-long escalators safe? Lessons learned from the Langham Place escalator incident in Hong Kong 超长自动扶梯安全吗？香港朗豪坊自动梯事件的教训

Transactions Hong Kong Institution of Engineers Pub Date : 2021-04-15 DOI: 10.33430/V28N1THIE-2019-0029

A. Ngan, K. Siu

{"title":"Are super-long escalators safe? Lessons learned from the Langham Place escalator incident in Hong Kong","authors":"A. Ngan, K. Siu","doi":"10.33430/V28N1THIE-2019-0029","DOIUrl":"https://doi.org/10.33430/V28N1THIE-2019-0029","url":null,"abstract":"Super-long escalators that are increasingly used in mega-cities take up a large number of passengers, and so their risk of sudden failure draws serious attention. As a case study, on 25 March 2017, an escalator with a 21 m elevation in Hong Kong’s Langham Place had its main drive chain suddenly snapped by metal fatigue, causing the escalator to reverse at an accelerating speed. A number of passengers were injured. In this paper, two issues will be discussed: (1) whether metal fatigue of the main drive chain can be detected with conventional protocols, and (2) what safety factor is needed to prevent metal fatigue. Analysis shows that initial fatigue cracks in escalator drive chains may not be easily detected with the commonly adopted maintenance protocol. Also, the time window from the emergence of clear signs of fatigue failure to the sudden snapping of the drive chain may be as short as weeks or even days, versus the common safety inspection intervals of six months. The safety factor to prevent metal fatigue of the drive chain should be at least 7, whereas lower values are currently allowed. It is suggested that the government should review the legal requirements to meet the recommended value.","PeriodicalId":35587,"journal":{"name":"Transactions Hong Kong Institution of Engineers","volume":"28 1","pages":"49-57"},"PeriodicalIF":0.0,"publicationDate":"2021-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47839158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Use of saturation diving technique for tunnel boring machine cutterhead intervention in the Tuen Mun–Chek Lap Kok Link Sub-sea Tunnel Project, Hong Kong 在香港屯门至赤角连接海底隧道工程中，隧道掘进机刀盘介入工程采用饱和潜水技术

Transactions Hong Kong Institution of Engineers Pub Date : 2021-04-15 DOI: 10.33430/V28N1THIE-2019-0044

A. Chan, Charles H C Yeung, A. Westmoreland, S. Fok, C. Ng, F. Guedon

{"title":"Use of saturation diving technique for tunnel boring machine cutterhead intervention in the Tuen Mun–Chek Lap Kok Link Sub-sea Tunnel Project, Hong Kong","authors":"A. Chan, Charles H C Yeung, A. Westmoreland, S. Fok, C. Ng, F. Guedon","doi":"10.33430/V28N1THIE-2019-0044","DOIUrl":"https://doi.org/10.33430/V28N1THIE-2019-0044","url":null,"abstract":"The entire Tuen Mun–Chek Lap Kok Link (TM-CLKL) was commissioned on 27 December 2020 and it comprises a 9km-long dual 2-lane carriageway between Tuen Mun and North Lantau, Hong Kong. Construction of the 5km-long sub-sea tunnels was carried out by two 14m diameter Tunnel Boring Machines (TBMs). The tunnel alignment for the TM-CLKL sub-sea tunnel section is in mixed ground condition with the first 500 m in mixed geology of slightly to moderately decomposed granite and completely decomposed granite (CDG), followed by soft ground condition with CDG, alluvial sand, alluvial clay and marine deposit. This mixed ground geology requires regular TBM cutterhead interventions to change the worn-out cutting tools during the tunnelling operation. As the tunnel alignment is up to 55 m below the sea level with the deepest seabed level at -21 mPD, in order to maintain the cutting face stability during the intervention, the intervention pressure could be up to 6 bars. This paper describes different techniques used for TBM interventions under the sea such as trimix bounce mode and saturation mode that appears first time in Hong Kong under a high hyperbaric pressure to change the worn-out cutting tools at the TBM cutterhead.","PeriodicalId":35587,"journal":{"name":"Transactions Hong Kong Institution of Engineers","volume":"28 1","pages":"31-38"},"PeriodicalIF":0.0,"publicationDate":"2021-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46652416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Special Issue with Awarded and Shortlisted Papers from the HKIE Outstanding Paper Award for Young Engineers/Researchers 2020 香港工程师学会青年工程师/研究人员杰出论文奖2020获奖论文和入围论文特刊

Transactions Hong Kong Institution of Engineers Pub Date : 2021-01-11 DOI: 10.33430/v27n4

引用次数: 0

Chillers of air-conditioning systems: An overview 空调制冷系统:概述

Transactions Hong Kong Institution of Engineers Pub Date : 2020-10-30 DOI: 10.33430/v27n3thie-2019-0055

M. Leung, C. Tso, Wei Wu, Zhanying Zheng, Jingyu Cao

引用次数: 2

Thermophilic co-digestion of food waste and sewage sludge 食物垃圾和污水污泥的嗜热共消化

Transactions Hong Kong Institution of Engineers Pub Date : 2020-10-30 DOI: 10.33430/v27n3thie-2019-0019

J. Li

引用次数: 0

Energetic and economic analysis of vapour compression refrigeration systems applied in different temperature ranges 不同温度范围下蒸汽压缩制冷系统的能量和经济分析

Transactions Hong Kong Institution of Engineers Pub Date : 2020-10-30 DOI: 10.33430/v27n3thie-2018-0035

Zhili Sun, Cui Qi, Qingzhao Liu, Caiyun Wang, Jiamei Li, Yang Lijie

{"title":"Energetic and economic analysis of vapour compression refrigeration systems applied in different temperature ranges","authors":"Zhili Sun, Cui Qi, Qingzhao Liu, Caiyun Wang, Jiamei Li, Yang Lijie","doi":"10.33430/v27n3thie-2018-0035","DOIUrl":"https://doi.org/10.33430/v27n3thie-2018-0035","url":null,"abstract":"To determine the suitable vapour compression refrigeration system for different temperature ranges, this paper established thermodynamic models for a single-stage vapour compression refrigeration system with an economiser (SSRS+E), a two-stage vapour compression refrigeration system (TSRS), and a cascade vapour compression refrigeration system (CRS) and conducted an energetic and economic analysis of it. The results show that compared with TSRS, SSRS+E can save energy by 13.6% and 7.1%, in the evaporating temperatures of -20°C and -25°C, respectively. R744/R717 CRS is superior to TSRS in terms of energy consumption and refrigeration unit investment costs. Compared with TSRS, R744/R717 CRS can save energy by 14.1% and 18.8%, in the evaporating temperatures of -45°C and -50°C, respectively. Based on the energetic and economic analysis, SSRS+E is recommended for use above the evaporating temperature of -25°C. TSRS is recommended for use in the evaporating temperature range of -45°C to -25°C, and R744/R717 CRS is recommended for use below the evaporating temperature of -45°C.","PeriodicalId":35587,"journal":{"name":"Transactions Hong Kong Institution of Engineers","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69753679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0