On the system of word equations x i 1 x i 2…x i m=y i 1 y i 2…y i n (i=1, 2, …) in a free monoid

 It is proved that the system of word equations x ⁱ ₁=y ⁱ ₁ y ⁱ ₂…y ⁱ _n , i=1, 2,…, ⌈n/2⌉ +1, has only cyclic solutions. Some sharpenings concerning the cases n=5, 7 and n≥9 are derived as well as results concerning the general system of equations x ⁱ ₁ x ⁱ ₂…x ⁱ _m =y ⁱ ₁ y ⁱ ₂…y ⁱ _n , i=1, 2,… . Applications to test sets of certain bounded languages are considered. Received: 18 May 1995/2 January 1996     

CAVE for collaborative patient room design: analysis with end-user opinion contrasting method

Several studies indicate that virtual reality (VR) systems are useful for end-user participation in an environmental design process. However, these systems can be costly and thus support for the decision whether to invest in a VR of some type is useful. This study presents a novel method for analysing the usefulness of a VR system for the purpose of end-user participation. We collected qualitative end-user opinion data in the real environment and then contrasted this data with the capabilities of a VR system. Additionally, to better understand the capabilities of the VR used, we examined how the end-users perceive the used virtual environment, which in this case was CAVE, an immersive VR system where projectors are directed to the walls of a room-sized cube. In this way, we analysed whether the same functions and elements identified by end-users on the actual wards could also be evaluated in the CAVE. Eleven nurses and 11 patients participated in the study by evaluating a bathroom and/or four patient rooms modelled by the CAVE and the actual hospital wards. The CAVE was convenient for evaluating most issues identified by the study participants in the actual hospital wards, i.e. aesthetics; correct location of equipment, supplies and materials; distraction by or the good companion of other patients as well as window position and size and living/workspace. However, it was not possible to evaluate with full certainty the possibilities for bracing against grab bars or other objects in the VR, and this was found to be relevant to the independent functioning of patients with limited mobility. Also, due to the relatively low luminance levels of projectors, evaluations regarding lighting were considered unreliable. Moreover, end-users were not always certain about the sizes and sufficiency of space in the CAVE. Solutions to overcome these limitations were proposed.     

双室平板玻璃钢化炉的质量和生产优势

夹层玻璃应用的显著增加和质量意识的总体提高，对钢化玻璃厂家在玻璃平面和光学质量方面提出了新的要求。这些对玻璃钢化行业的要求主要在建筑和太阳能市场，这两个市场对夹层玻璃质量的要求更加突出。除了质量以外，本文还设法解决玻璃处理领域的最大趋势一能效问题。本文从两个角度讨论双室处理的能效问题：（1）三银镀膜玻璃比重的日益提高及它们对生产的要求；（2）双室生产线生产每平米玻璃所消耗能源的能效。本文的目的是通过实例来说明逐步增温的双室处理方式的优点，并找出用于两段式加热法的加热技术的最佳解决方案，以保证平板玻璃钢化生产线能够满足日益提高的质量要求。     

机械制造商未来服务理念的一个策略性选择

一、简介 当制造企业以其核心业务为重点时,业务外包和外委服务的方式成为资产管理的一个选择。新的生产模式是建立在协作网络的基础上的,其中如维修、设计和物流由服务者提供,并与企业的工作紧密协作。未来价值网络可能取代价值链,在价值网络中,对于产品和提供的服务,公司提供补充功能和所有资本都是必要的。     

A methodology for systematic mapping of heat sources in an urban area

The increased use of heat pumps to utilise low-temperature heat will undoubtedly be a part of future emission reduction measures within the heating sector. Identifying these heat sources and assessing their heat potential is essential for their utilisation. Different methods for estimating the potential of excess and natural heat sources found in the urban environment are presented in this study. The research aims to present a replicable estimation methodology which can be applied to any urban area. The methods are developed around publicly available data sources, or otherwise easily obtainable data. The research aims at producing data accurate enough to support decision-making on the district heating company or city level on utilising these heat sources. A wide range of excess and natural heat sources found in urban environments were identified in a literature review. Methods for estimating the potential of the heat sources were developed based on findings of the literature review and the expected availability of data. The developed estimation methods were applied in a case study where the potential of heat sources identified within the Turku area in Southwest Finland was estimated. The results of the case study show the potential of the heat sources within the studied area. The difficulty of obtaining raw, high-quality data are also highlighted. This emphasises the need for advanced processing of available data and insight on the related sources, e.g. building management systems or industrial processes. The methods presented in this study give an overview on how heat potential could be estimated. It can be used as a base for developing more refined methods and for detailed techno-economic assessment for utilising available excess and natural heat sources.

Graphical abstract

     

Forecasting the unresponsiveness to verbal command on the basis of EEG frequency progression during anesthetic induction with propofol

The objective of this study is to model the association between the electroencephalogram (EEG) spectral features and the novel r scale representing the sedative effects of the propofol anesthetic drug. On the basis of the r scale, the unresponsiveness to the verbal command (LVC) is forecasted. EEG recordings are taken from a 16-patient study population undergoing propofol anesthetic induction. EEG was filtered into consecutive 4-Hz passbands up to 28 Hz. Of these time-series, the amplitude envelopes were extracted and used as input features to the first and the second-order polynomial multiple linear regression models. The values r epsilon [0.4, 1] were predicted with the R2 value of 0.775 with a cross validation. The LVC times were forecasted with the median error of 5%-7% or equivalently 10-13 s. In contrast, using the median of the measured LVC times of the training population as a forecast, the corresponding error was 12% or 26 s. The results suggest an acceptable correlation between the r scale and the EEG spectrum in the studied range. Moreover, the r values of an individual can be predicted using a population model. The suggested framework enables forecasting the LVC, which may open new possibilities for steering the drug administration.     

Nitrogen in river basins: sources, retention in the surface waters and peatlands, and fluxes to estuaries in Finland

Nitrogen export from diffuse and point sources and its retention in the major river basins of Finland is quantified and discussed. The estimated total export from river-basins in Finland was 119,000 tonnes N a(-1) for the period 1993 to 1998 based on N export from different land use types defined in a GIS-based assessment model, incorporated with estimates of N inputs from atmospheric deposition and point sources. Agriculture contributes 38% of the total export, varying in the range 35-85% in the south-western basins and 0-25% in the northern basins. This estimate of N export from agriculture was based on regional N balances together with data from small agricultural research catchments. Forestry contributes on average 9%, with increasing dominance towards eastern and northern parts of the country: from 2% to 15% in the southern-mid-western Finland basins to 10-30% in the large northern basins. 'Background' N export from forests on both mineral and organic soils contributes 27% on average; in the northern basins it may contribute from 40% up to 90% of the total load. The estimate was calculated based on practically all data available from 42 small, experimental catchments in Finland. Of the total N input to Finnish river-systems, 0% to 68% was retained in surface waters and/or peatlands, with a mean retention of 22%. The highest retention of N (36-61%) was observed in the basins with the highest lake percentages. The lowest retention (0-10%) of N was in the coastal basins with practically no lakes. In the national N mass balance, 38,000 tonnes N a(-1) (32%) was estimated as lake retention and 4,000 tonnes N a(-1) (3%) as retention in peatlands. On the basis of mass balances and sensitivity analysis, retention was in most cases estimated to be in the range of 7.5-12.5 kg ha(-1)a(-1) in lakes and 0-1.5 kg ha(-1)a(-1) in peatlands. The model results were tested using the split-sample technique and uncertainty estimates for different data sources are provided and discussed.     

Extent and composition of coronary lesions and degree of cardiac hypertrophy in relation to abdominal fatness in men under 40 years of age

The relationship of the extent and composition of coronary lesions and the degree of cardiac hypertrophy to anthropometric indicators of abdominal fatness and the amount of intra-abdominal fat was investigated in a group of 32 forensic autopsy cases that consisted of sudden deaths from violent causes of previously healthy men under 40 years of age. Body height and weight, waist and hip circumferences, and the thickness of the subscapular and abdominal subcutaneous fat were measured; the body mass index (BMI) and waist-to-hip ratio (WHR) were calculated; and omental, mesenteric, and perirenal fat deposits and the heart were weighed. The degree of coronary narrowing was determined visually, and the extent of coronary lesions was measured by planimetry. The thickness of the intima and intima-media was measured by computerized image analysis. Intimal macrophage foam cells and smooth muscle cells were detected by immunohistochemistry. Significant positive correlations were found between WHR and the overall degree of coronary narrowing and the intima-media thicknesses of the left anterior descending artery and right coronary artery when adjusted for age. Intima-media thickness was also related to tertiles of WHR. Heart weight indexed to height showed a significant positive correlation with BMI, waist circumference, WHR, and the size of intra-abdominal fat deposits, of which WHR was the best predictor of mild cardiac hypertrophy. The results indicate that the severity of clinically silent lesions in the atherosclerosis-prone regions of the coronary arteries is associated with WHR in young male individuals who also have mild myocardial hypertrophy associated with abdominal fatness and an accumulation of intra-abdominal fat. These associations between fat distribution and early cardiovascular changes point to a powerful need for preventive action with respect to weight gain in young men to alleviate progression of the lesions.     

Combining Web of Science and Scopus datasets in citation-based literature study

Scientometrics - Scientific research builds on previous studies and scientifically proven knowledge. Researchers must master the recent developments in the field when designing research to answer...