scholarly journals Stability analysis of geomagnetic baseline data obtained at Cheongyang observatory in Korea

2017 ◽  
Author(s):  
Shakirah M. Amran ◽  
Wan-Seop Kim ◽  
Heh Ree Cho ◽  
Po Gyu Park

Abstract. The stabillity of baselines produced by Cheongyang (CYG) observatory from a period of 2014 to 2016 is analysed. Step height of higher than 5 nT were found in H and Z components in 2014 and 2015 due to magnetic noise in the absolute measurement hut. In addition, a periodic modulation behaviour observed in the H and Z baseline curves was related to temperature variation of about 20 °C in the fluxgate magnetometer hut. The quality of the baselines was improved by correcting the discontinuity in the H and Z baselines. Moreover, the stability of the both baselines was also improved by about 6 nT/year from 10 nT/year by performing the temperature effect correction.

2017 ◽  
Vol 6 (2) ◽  
pp. 231-238
Author(s):  
Shakirah M. Amran ◽  
Wan-Seop Kim ◽  
Heh Ree Cho ◽  
Po Gyu Park

Abstract. The stability of baselines produced by Cheongyang (CYG) observatory from the period of 2014 to 2016 is analysed. Step heights of higher than 5 nT were found in H and Z components in 2014 and 2015 due to magnetic noise in the absolute-measurement hut. In addition, a periodic modulation behaviour observed in the H and Z baseline curves was related to annual temperature variation of about 20 °C in the fluxgate magnetometer hut. Improvement in data quality was evidenced by a small dispersion between successive measurements from June 2015 to the end of 2016. Moreover, the baseline was also improved by correcting the discontinuity in the H and Z baselines.


2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Luyun Xu ◽  
Dong Liang ◽  
Zhenjie Duan ◽  
Xu Xiao

R&D outsourcing becomes the often-adopted strategy for firms to innovate. However, R&D cooperation often ends up with failure because of its inherent quality of instability. One of the main reasons for cooperation failure is the opportunistic behavior. As the R&D contract between firms is inherently incomplete, opportunistic behavior always cannot be avoided in the collaborative process. R&D cooperation has been divided into horizontal and vertical types. This paper utilizes game theory to study opportunistic behavior in the vertical R&D cooperation and analyzes the equilibrium of the cooperation. Based on the equilibrium and numerical results, it is found that the vertical R&D cooperation is inherently unstable, and the downstream firm is more likely to break the agreement. The level of knowledge spillovers and the cost of R&D efforts have different effects on firms’ payoffs. When the level of knowledge spillover is low or the cost of R&D efforts is high, mechanisms such as punishment for opportunism may be more effective to guarantee the stability of cooperation.


Mechanik ◽  
2017 ◽  
Vol 90 (11) ◽  
pp. 965-967
Author(s):  
Piotr Andrzej Bąk ◽  
Krzysztof Jemielniak

Self-excited vibrations significantly reduce the milling productivity, deteriorate the quality of machined surface and tool life. One of the ways to avoid these vibrations is to modify the cutting parameters based on the stability analysis results. A method of numerical simulation of self-excited vibrations in the time domain can be used for this purpose. A comparison of numerical simulation results with those from experiments conducted using a milling machine is presented. The results confirm the correctness of applied modeling.


2020 ◽  
Vol 15 (2) ◽  
pp. 114-122
Author(s):  
Teddy Wartono Sudinda

Abstract The collapse of the embankment is a problem that needs attention to find the right solution, so that the risk can be minimized. The condition of the embankment is influenced by the strength of the soil layer of the embankment, groundwater flow in the embankment, the condition of the water level of the embankment and human activities around the embankment. Changes in the quality of soil density in the embankment can form cavity zones within the embankment which cause changes in groundwater flow patterns in the embankment. The degradation of the soil layer of the embankment can cause piping, overtopping which is the cause of erosion of the embankment body and disturbs the stability of the embankment. Therefore, to determine the condition of the embankment soil layer, research on the stability of the embankment has been carried out using the geoelectric method at the location of the embankment in the Cipancuh and Penjalin reservoirs, so that an image of the embankment soil layer is obtained to determine the cavity zones in the embankment, the flow pattern in the embankment soil layer. Keywords:  cavity zones, flow patterns, geoelectric methods, the stability of the embankment.


2020 ◽  
Vol 25 (1) ◽  
pp. 205-231
Author(s):  
Alexandre Nascimento de Almeida ◽  
Lussara Ribeiro Vieira Marques ◽  
Luciana de Oliveira Miranda ◽  
Jonilto Costa Sousa ◽  
Mario Lucio de Ávila

ABSTRACT The functions of university libraries (UL) are to provide the bibliographic, documentary and informational infrastructure to support scientific activities, as well as to disseminate the knowledge produced by their academic entity to society. To achieve their mission, ULs need to be evaluated and, in Brazil, this evaluation is done by the National Student Performance Exam (ENADE - ExameNacional de Desempenho de Estudantes) through the Student Questionnaire (SQ). The present study evaluated the quality of the indicators used in the SQ for the evaluation of ULs. This quality was evaluated by considering the presence of the following essential properties for good indicators: stability, validity and importance of parameters. For the stability analysis, the SQ questions were repeated in the period from 2004 to 2014. Regarding the validity, a correlation analysis was performed between the results obtained in the SQ with another theoretically related indicator. For the analysis of the importance, a group of specialists was formed, composed of librarians with experience in the management of ULs and, through the Delphi method, indicators were evaluated as to their relevance. This work verified that the indicators used by ENADE are considered important, but they do not have stability and validity.


2002 ◽  
Vol 12 (03n04) ◽  
pp. 177-186 ◽  
Author(s):  
BRENTON COOPER

Recurrent neural networks with higher order connections, from here on referred to as higher-order neural networks (HONNs), may be used for the solution of combinatorial optimization problems. In Ref. 5 a mapping of the traveling salesman problem (TSP) onto a HONN of arbitrary order was developed, thereby creating a family of related networks that can be used to solve the TSP. In this paper, we explore the trade-off between network complexity and quality of solution that is made available by the HONN mapping of the TSP. The trade-off is investigated by undertaking an analysis of the stability of valid solutions to the TSP in a HONN of arbitrary order. The techniques used to perform the stability analysis are not new, but have been widely used elsewhere in the literature.15–17 The original contribution in this paper is the application of these techniques to a HONN of arbitrary order used to solve the TSP. The results of the stability analysis show that the quality of solution is improved by increasing the network complexity, as measured by the order of the network. Furthermore, it is shown that the Hopfield network, as the simplest network in the family of higher-order networks, is expected to produce the poorest quality of solution.


2018 ◽  
Vol 7 (2) ◽  
pp. 144
Author(s):  
Zeth Arthur Leleury ◽  
Yopi Andry Lesnussa ◽  
Johan Bruiyf Bension ◽  
Yulia S. Kakisina

Health is an investment to support economic development and has an important role in efforts to reduce poverty and improve the quality of human resources. One of the diseases that often become serious problem in health sector that is Dengue Hemorrhagic Fever (DHF). In Indonesia, many mosquitoes cause dangerous DHF such as Aedes aegypti, Aedes albopictus, Aedes africanus, anopheles and others. In this study, we analyzed and applied SIR (Susceptible, Infection, Recovered) mathematical models and their interpolation to determine whether a contagious disease (DHF) can become endemic or not. Therefore, in this study aimed to determine the a special form of model of SIR to analyze the spread of DHF in Maluku Province and the stability analysis of this model and also interpolating the data of DHF transmission in Maluku Province. Furthermore, it can be obtained the characteristics of equilibrium point of each sub population. Based on the research conducted it can be concluded that from the entire population of Maluku Province is 1.686.469 vulnerable people infected with DHF and endemic disease with the basic reproduction value is 3,44.


2019 ◽  
pp. 3-8
Author(s):  
N.Yu. Bobrovskaya ◽  
M.F. Danilov

The criteria of the coordinate measurements quality at pilot-experimental production based on contemporary methods of quality management system and traditional methods of the measurements quality in Metrology are considered. As an additional criterion for quality of measurements, their duration is proposed. Analyzing the problem of assessing the quality of measurements, the authors pay particular attention to the role of technological heredity in the analysis of the sources of uncertainty of coordinate measurements, including not only the process of manufacturing the part, but all stages of the development of design and technological documentation. Along with such criteria as the degree of confidence in the results of measurements; the accuracy, convergence, reproducibility and speed of the results must take into account the correctness of technical specification, and such characteristics of the shape of the geometric elements to be controlled, such as flatness, roundness, cylindrical. It is noted that one of the main methods to reduce the uncertainty of coordinate measurements is to reduce the uncertainty in the initial data and measurement conditions, as well as to increase the stability of the tasks due to the reasonable choice of the basic geometric elements (measuring bases) of the part. A prerequisite for obtaining reliable quality indicators is a quantitative assessment of the conditions and organization of the measurement process. To plan and normalize the time of measurements, the authors propose to use analytical formulas, on the basis of which it is possible to perform quantitative analysis and optimization of quality indicators, including the speed of measurements.


Author(s):  
N.A. Jurk ◽  

The article presents scientific research in the field of statistical controllability of the food production process using the example of bakery products for a certain time interval using statistical methods of quality management. During quality control of finished products, defects in bakery products were identified, while the initial data were recorded in the developed form of a checklist for registering defects. It has been established that the most common defect is packaging leakage. For the subsequent statistical assessment of the stability of the production process and further analysis of the causes of the identified defect, a Shewhart control chart (p-card by an alternative feature) was used, which allows you to control the quality of manufactured products by the number of defects detected. Analyzing the control chart, it was concluded that studied process is conditionally stable, and the emerging defects are random. At the last stage of the research, the Ishikawa causal diagram was used, developed using the 6M mnemonic technique, in order to identify the most significant causes that affect the occurrence of the considered defect in bakery products. A more detailed study will allow the enterprise to produce food products that meet the established requirements.


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