► Proposes an adaptive, recursive clustering procedure capable for novelty detection. ► Presents a real-time implementation of the proposed adaptive classifier. ► Illustrates capability and ...performance of the classifier in the case of fault detection and process monitoring. ► The proposed expert system is capable of identifying novel, previously unseen, working condition on line.
An adaptive clustering procedure specifically designed for process monitoring, fault detection and isolation is presented in this paper. The key feature of the proposed procedure can be identified as its underlying capability to detect novelties in the system’s mode of operation and, thus, to identify previously unseen functioning modes of the process. Once a novelty is detected, relevant informations are used to enrich the knowledge-base of the algorithm and as a result the proposed clustering procedure evolves and learns the new features of the monitored process in accordance with the available process data. The suggested clustering procedure is theoretically illustrated and its effectiveness has been investigated experimentally. Particularly, the on-line implementation of the algorithm and its integration with a fault detection expert system have been considered by making reference to a pneumatic process.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Identification of predictive factors for walking ability with a prosthesis, after lower limb
amputation, is very important in order to define patient’s potentials and realistic rehabilitation goals,
...however challenging they are.
The objective of this study was to investigate whether variables determined at the beginning
of rehabilitation process are able to predict walking ability at the end of the treatment using support
vector machines (SVMs).
This research was designed as a retrospective clinical case series. The outcome was defined as
three-leveled ambulation ability. SVMs were used for predicting model forming.
The study included 263 patients, average age 60.82 ± 9.27 years. In creating SVM models, eleven
variables were included: age, gender, cause of amputation, amputation level, period from amputation to
prosthetic rehabilitation, Functional Comorbidity Index (FCI), presence of diabetes, presence of a partner,
restriction concerning hip or knee extension, residual limb hip extensor strength, and mobility at admission.
Six SVM models were created with four, five, six, eight, 10, and 11 variables, respectively. Genetic
algorithm was used as an optimization procedure in order to select the best variables for predicting the
level of walking ability. The accuracy of these models ranged from 72.5% to 82.5%.
By using SVM model with four variables (age, FCI, level of amputation, and mobility at admission)
we are able to predict the level of ambulation with a prosthesis in lower limb amputees with
high accuracy.
► Concept of leaning and badly shaped junctions were the cause of cracks appearance. ► The intuitive attempt to reinforce the girders was unsuccessful. ► The solution to the problem was found in the ...redesign of the junctions. ► After the presented reconstruction no damages of the structure were observed.
The traveling mechanism of the C-700S bucket wheel excavator is of the two-crawler type. Rigid connections between the undercarriage and the crawler beams offer a very high factor of safety against tipping but at the same time create unfavorable conditions for ground surface adaptation. Connections between the crawler beams and the undercarriage cylindrical girder were realized by means of connection girders with open cross sections (I sections). In order to eliminate the occurrence of cracks, the original undercarriage structure (variant I) has been redesigned (variant II). The key idea was to strengthen the already mentioned connection girders by building in vertical plates. In this way the cross-sections were closed and their torsional rigidity became considerably greater, which led to the adaptation of the traveling mechanism to the ground surface becoming practically impossible. Because of that alone, and within a very short period after the reconstruction, new cracks occurred on elements of the original structure and even on added structural elements. Based on the FEA results, it was concluded that cracks occurrence for variants I and II of the undercarriage structure is caused by highly pronounced stress concentration. Subtle load and stress analyses in various working regimes, presented in the paper, led to the achievement of a re-redesigned undercarriage structure (variant III) with more uniform stress distribution. Stress level in the critical zone for variant III of the undercarriage structure is considerably lower than stress levels for both variant I (≈2.1 times) and variant II (≈2.5 times). It is very important to note that the weight of the new built-in elements for variant II is six times greater than that for variant III. During ensuing exploitation in extremely heavy duty conditions, no damages for variant III of the considered structure were observed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•We examined the causes for the damage of the BWE crawler chain links.•Chain link breakdowns are caused by ‘manufacturing-in’ defects.•The results emphasize the importance of a comprehensive quality ...control.
The high mobility of open pit machines in heavy duty conditions provides fertile ground for the occurrence of various failures of the traveling mechanisms’ vital parts such as chain links. The goal of the study presented in this paper was to diagnose the cause of the damage of the bucket wheel excavator crawler chain links. In order to identify the reasons behind chain link failures, stress state calculations were performed as well as experimental investigations which, given the nature of the failure, included visual and metallographic examinations, chemical composition analysis and tests of mechanical properties. Based on the results of the numerical–experimental analyses, it was concluded that the chain link breakdowns are caused by ‘manufacturing-in’ defects. The results of the presented analyses also emphasize the importance of a comprehensive quality control of chain links.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•We examined the causes for the damage of the supporting truss columns’ heads.•The columns’ heads failures are caused by ‘designing-in’ defects.•The redesign solution enabled repair and ...reconstruction in field conditions.•Results of in situ measurements fully confirmed the validity of the redesign concept.•After the presented reconstruction no damages of the structure were observed.
The supporting truss of the counterweight boom is a vital part of the bucket chain excavator’s (BCE) superstructure. The occurrence and propagation of cracks in the supporting truss columns’ heads may lead to BCE collapse. The goals of the study presented in this paper were to: (a) diagnose the cause of cracks occurrence; (b) define the reconstruction design of the supporting truss columns and (c) validate the reconstructed structure by numerical–experimental analysis. In order to clarify the causes of cracks occurrence, experimental investigations were performed with the purpose of defining the chemical composition, tensile properties, impact toughness and macrohardness of the columns’ material. Metallographic examinations were also conducted. Based on the results of finite elements analyses (FEA) and experimental analyses it can be concluded that cracks are caused by the ‘design-in’ defects. The redesign solution enabled repair and reconstruction in field conditions, without previously dismantling any substructure of the BCE superstructure. Thereby the time required for performing reconstruction is shortened and indirect costs due to the BCE downtime are considerably diminished. Both the experimental analysis of the stress state of the reconstructed columns in regular working conditions and the failure-free exploitation have confirmed the validity of the reconstruction design, while the BCE excavated approximately 8.5×106t of coal and 1.8×106m3 of overburden after the reconstruction.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Failures of the cranes’ structural parts unavoidably lead to serious damages or total collapses; these accidents are often followed by very high financial losses and possibly serious injuries or ...crane-related fatalities. The objective of this research was to identify the causes that led to the failure of the hammerhead tower crane (xl425C) counterjib. The crane is used for assembly works at the hydropower dam. The counterjib collapse resulted from a gusset plate failure and caused such significant damage of the whole crane structure that the crane was dismantled and removed from operation. The study of the accident includes: (1) Identification of the stress-state, where a FEM model is developed to provide a useful tool for studying stress analysis; (2) Laboratory investigations are conducted in order to define the chemical composition and mechanical properties of the material, the tensile properties, hardness, impact toughness, as well as the metallographic analyses. The analysis of the obtained results showed that the principal reasons behind the gusset plate failure originated from design and fabrication faults. The working stress was higher than the allowable one. Also, impact toughness was too low and the fabrication of welds was incorrect.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Objective Injuries of the ureter or bladder or development of vesicovaginal and ureterovaginal fistulas are the most serious complications in gynecological surgery. Study Design This study included ...536 women who underwent radical hysterectomy because of invasive cancer of the cervix uteri. Results During the surgery the ureter was injured in 1.32% of cases, whereas the percentage of bladder injuries was 1.49. In the early postoperative period vesicovaginal or ureterovaginal fistulas appeared in 2.61% and 2.43% of cases, respectively. Conclusion The stage of the disease, obesity, diabetes, and postoperative surgical infection acted as predisposing factors of the urinary tract complications.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Autism is a hereditary, pervasive neurodevelopmental disorder that starts early in life. The main characteristics of the autism are impairment in social interactions, difficulties in adapting to ...novel environmental situations and improper reaction to stress. Since the Hypothalamic-Pituitary-Adrenocortical (HPA) axis plays a key role in the response to stress and because the previous research found abnormalities in HPA system, we conducted a study to test several elements of the HPA axis. Because autism is a heritable disorder, autistic subjects were studied as well as their parents. Cortisol circadian rhythm, cortisol daily secretion and its suppression response to dexamethason had been measured from saliva or urine samples of the autistic children and their parents. Cortisol secretion response after ACTH stimulation was done with the autistic children only. The cortisol elevation after ACTH stimulation among the autistic individuals was slower (
P
= 0.017) than in healthy controls. No differences were found in salivary cortisol circadian rhythm or suppression response, as well as in cortisol daily excretion. These data indicate that, compared to healthy subjects, autistic individuals have fine differences in cortisol response to ACTH stimulation or possibly to other types of stress.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, ODKLJ, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, VSZLJ, ZAGLJ
A very important parameter for the utilization of medicinal plants is the quality of active substances. The quality of the plant active substances does not depend only on its physiological potential ...and condition, but also on the environmental factors. The status of microelements in the soil and the basic ecological indices of plants, as the site indicators, at two localities on Mt. Kosmaj are presented. It was concluded that these relationships are very complex, in most cases identical and in direct correlation with the representation of individual plant species. Medicinal plants were analyzed in the first place because of their potential exploitation.
Za upotrebu lekovitih biljaka veoma je vazan kvalitet aktivnih supstanci koje sadrze. Kakav kvalitet aktivnih supstanci ce biljka posedovati, ne zavisi samo od njenog fizioloskog potencijala i kondicije vec i od faktora spoljasnje sredine. U radu su prikazani rezultati istrazivanja statusa makroelemenata u zemljistu i osnovni ekoloski indeksi biljaka, kao indikatora stanista, na dva lokaliteta na Kosmaju. Utvrdjeno je da su ovi odnosi veoma kompleksni, u vecini slucajeva podudarni i u direktnoj korelaciji sa zastupljenoscu odredjenih biljnih vrsta. Prvenstveno su obradjene lekovite biljke zbog mogucnosti njihovog koriscenja.
In the paper the results of study of soil ecological quality in the area of Kosmaj (Serbia, Serbia&Montenegro), from the aspect of chemical degradation process, are presented. The aim of this ...investigation is to define the possible, limiting and endangered factors for development of medicinal and aromatic plants. The estimate of soil quality was done on the bases of calculation of indicator values of availability of nitrogen (N), phosphorus (P), base cations and heavy metals and sensitivity to acidification.
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