Rapid computation of far-field statistics for random obstacle scattering

In this article, we consider the numerical approximation of far-field statistics for acoustic scattering problems in the case of random obstacles. In particular, we consider the computation of the expected far-field pattern and the expected scattered wave away from the scatterer as well as the computation of the corresponding variances. To that end, we introduce an artificial interface, which almost surely contains all realizations of the random scatterer. At this interface, we directly approximate the second order statistics, i.e., the expectation and the variance, of the Cauchy data by means of boundary integral equations. From these quantities, we are able to rapidly evaluate statistics of the scattered wave everywhere in the exterior domain, including the expectation and the variance of the far-field. By employing a low-rank approximation of the Cauchy data's two-point correlation function, we drastically reduce the cost of the computation of the scattered wave's variance. Numerical results are provided in order to demonstrate the feasibility of the proposed approach

Law and economics of employee inventions

У дисертацији аутор настоји да одговори на питање да ли право на патентну заштиту и привредну употребу проналаска који је створен у радном односу треба признати послодавцу или проналазачу и под којим условима. Повод за истраживање пружају бројни радови у којима се заговара боља правна заштита проналазача и законска решења у упоредном праву која признају послодавцу право на патентну заштиту под различитим условима. Како би дошао до одговора, аутор анализира историјски развој института патентне заштите и релевантна законска решења из упоредних патентних система, при чему поред правних метода примењује и економске методе и моделе. На основу истраживања, аутор закључује да би право на патентну заштиту проналаска створеног у радном односу требало признати послодавцу, под обавезујућим условом да усвоји одговарајући интерни систем подстицаја, који би проналазачима омогућио да преузимају део ризика (и користи од) истраживања и развоја. На тај начин би били створени бољи подстицаји за улагање у истраживање и развој и за ефикасније обављање истраживачких делатности код послодавца, што би у крајњем ефекту могло позитивно да утиче на технолошки и економски развој друштва.In the dissertation, the author tries to answer the question of whether the right to patent protection and commercial exploitation of employee inventions should be granted to employers or employed inventors, and under which conditions. The reason for the research lies within numerous papers advocating stronger legal protection of employed inventors, and comparative legal systems granting the right to patent protection to employers under different conditions. In order to provide an answer, the author analyzes the historical development of patent protection, and comparative legal solutions in modern patent systems, applying the legal methods, and economics methods and models. Based on the conducted analysis, the author concludes that the right to patent protection of employee inventions should be granted to an employer, under the mandatory condition to enact adequate internal incentive system for employed inventors, which would enable inventors to take a share of research and development risk (and profit). In that way, one could create better incentives for investments in research and development, and for more efficient conduct of scientific and research activities within employers’ organization, which could contribute to the technological and economic development of a society

CISPLATIN - AN OVERVIEW OF ITS EFFICIENCY AND TOXICITY

Cisplatin is the first heavy metal compound that has been found to possess antineoplastic activity. It is effective in treating testicular, ovarian, head and neck, bladder, cervical, esophageal tumors, and small cell lung carcinoma. Approximately 1% of cisplatin that enters the cell interacts with DNA, forming DNA-cisplatin bonds. Both apoptosis and necrosis can be found in the same population of cells exposed to cisplatin, and the mode of cell death depends on the cisplatin concentration and metabolic state of the target cell. In the bloodstream, the platinum component of cisplatin binds to the blood's proteins (hemoglobin, albumin and transferrin), and other significant portion binds to the glutathione and other cysteine-rich biomolecules. Cisplatin impairs the mitochondrial and cell antioxidant defense system (decreases GSH, NADPH levels, GCH/GSSG ratio, and increases GSSG levels) leading to oxidative stress. There are three main mechanisms of cell resistance to cisplatin: (1) enhanced repair of cisplatin-induced DNA lesions, (2) decrease in uptake and/or increase in efflux and (3) inactivation of cisplatin intracellularly. The usage of cisplatin is limited due to its toxicity and side effects, which include neurotoxicity (numbness and tingling, paresthesia, reduced deep tendon reflexes), nephrotoxicity (renal insufficiency, hypomagnesemia), ototoxicity (tinnitus and bilateral high-frequency hearing loss), cardiotoxicity (changes in electric heart activity, congestive heart failure), gastrotoxicity (nausea, vomiting, and dyspepsia), etc.  So far, there  has been no effective, clinically administered, therapy for cisplatin-induced toxicity

Rapid computation of far-field statistics for random obstacle scattering

In this article, we consider the numerical approximation of far-field statistics for acoustic scattering problems in the case of random obstacles. In particular, we consider the computation of the expected far-field pattern and the expected scattered wave away from the scatterer as well as the computation of the corresponding variances. To that end, we introduce an artificial interface, which almost surely contains all realizations of the random scatterer. At this interface, we directly approximate the second order statistics, i.e., the expectation and the variance, of the Cauchy data by means of boundary integral equations. From these quantities, we are able to rapidly evaluate statistics of the scattered wave everywhere in the exterior domain, including the expectation and the variance of the far-field. By employing a low-rank approximation of the Cauchy data's two-point correlation function, we drastically reduce the cost of the computation of the scattered wave's variance. Numerical results are provided in order to demonstrate the feasibility of the proposed approach

Processing, properties and application of bismuth ferrite-based multiferroic materials.

Bizmut-ferit (BiFeO3) ispoljava jedinstvena svojstva koja pre svega doprinose teorijskom shvatanju električnih i magnetnih uređenja i njihove interakcije u kristalnim oksidnim materijalima, ali bi uz prevazilažanje trenutno postojećih prepreka materijala na bazi bizmut-ferita mogli naći primenu u mnogim oblastima. Postoji samo nekoliko jednofaznih materijala kojima se može pripisati više feroičnih svojstava (feroelektrična, feroelastična, (anti)feromagnetna) na temperaturama višim od 50 K. Zbog toga ne čudi da je baš bizmut-ferit, koji i na temperaturama iznad sobne može ispoljiti feroelektričnost, feroelastičnost, pa čak i slab feromagnetizam (iako je po magnetnoj strukturi antiferomagnetan), predmet istraživanja brojnih naučnih radova iako i dalje ne postoje uređaji koji u sastavu sadrže bizmut-ferit...Bismuth ferrite (BiFeO3) theoretically possesses very peculiar properties, and understanding them may be the key of understanding the nature of interaction between electrical and magnetic orderings in crystalline oxides. If problems in exhibiting those properties were overcome, bismuth ferrite-based materials might be widely applicable. Few single phase materials exhibit two or three of the ferroic properties (ferroelectric, ferroelastic, (anti)ferromagnetic) at temperatures above 50 K. Being ferroelectric, ferroelastic and even weakly ferromagnetic (although possessing antiferromagnetic structure of magnetic spins) at temperatures well above the room temperature, bismuth ferrite is the subject of hundreds of scientific studies with good reason, although its application is still far from being realized..

Efficiency of modified therapeutic protocol in the treatment of some varieties of canine cardiovascular dirofilariasis

The paper presents clinical diagnostic approaches and therapeutic effects of a specific protocol for the treatment of dogs with cardiovascular dirofilariasis in the Belgrade City (Serbia) territory. The study involved 50 privately owned dogs of different breeds, gender, and age, all showing signs of cardio respiratory disorders. In addition to a general physical examination, blood tests were done to detect microfilaria and adult forms, and X-ray, ECG, and echocardiography were performed as well. At the first examination, 34 out of 50 examined dogs were positive for microfilaria and adult forms. Because of a lack of drug used as the golden standard in dirofilariasis treatment, it involved a combination of doxycycline (10 mg/kg) and ivermectin (6 mu g/kg) supported with Advocate Bayer spot-on. After six months, the first control was performed while continuing treatment with the aforesaid protocol, and the second control was performed after 12 months. Of the 34 treated dogs, all were negative for microfilaria, as early as after the first six months of the treatment (100%). One dog was positive for adult forms of the parasite after six and 12 months. In echocardiography and X-ray examination after 12 months, six dogs showed evident chronic changes. At controls conducted at sixth month and at one year, the implemented therapy was successful in 97.05% (33/34) of primarily infected dogs

On ultimate strength of an inland waterway barge

Due to the sudden nature of hull girder collapse caused by extreme loadings, the ultimate strength of ships, i.e., ultimate capacity, has to be evaluated. Ultimate strength analysis procedures have already been provided within the rules of the classification societies for sea-going ships. However, rules for inland vessels are not fully addressing the issue. In addition, literature data on the ultimate strength of inland vessels are almost negligible, which is alarming, considering the frequency of grounding and overloading events in inland navigation. Moreover, inland vessels' structural elements are prone to buckling due to their slender plates. In order to evaluate ultimate strength, an inland waterway (IW) barge is chosen for progressive collapse analysis (PCA) employment. PCA has demonstrated that the buckling collapse of structural elements vastly governs a vessel's ultimate capacity. Results show the extent of the safety zone between the actual loss of the ultimate capacity and the linear-elastic behavior of the structure

Procena indirektnih troškova usled prekida putne veze zbog smanjenja funkcionalnih performansi mosta

Stability and bearing capacity of the most important engineering structures of road sections (bridges, tunnels, viaducts, etc...) have enormous influence on the functional performance of the entire highway network. The bridges over torrential rivers are the most vulnerable, which unfortunately has been manifested in May floods in 2014 on the large part of the Serbian national highway network. Structural damage on bridges, inflicted in floods, reduce bearing capacity and designed traffic flow performance of bridges, as well as their capacity to provide safe traffic for all road users. In addition to the direct costs related to the reconstruction of the bridge structure, a partial restriction or in the worst case total traffic suspension due to bridge collapse, leads to a significant increase of indirect costs of road users. In fact, topic of this paper is efficient assessment of the indirect costs due to partial or complete closure of highway section due to damage on bridge structural elements. The VISUM simulation model of one part of the Serbian national highway network was used as a basis for the vulnerability assessment of links that cross over the bridges endangered by floods.Stabilnost i nosivost najvažnijih inženjerskih objekata na deonicama puta (mostovi, tuneli, vijadukti, itd.) imaju ogroman uticaj na funkcionalne performanse cele putne mreže. Najviše su ugroženi mostovi preko bujičnih reka, što je na žalost i potvrđeno tokom majskih poplava 2014. na većem delu putne mreže Srbije. Oštećenja na konstrukciji mosta, nastala u poplavama, smanjuju nosivost i projektovani kapacitet mostova, kao i njihovu sposobnost da obezbede siguran saobraćaj za sve korisnike putne deonice na kojoj se oni nalaze. Delimična obustava ili u najgorem slučaju potpuni prekid saobraćaja usled rušenja mosta, pored direktnih troškova vezanih za obnovu mostovske konstrukcije, dovode do značajnog rasta indirektnih troškova korisnika puta. Tema ovog rada je upravo efikasna procena indirektnih troškova usled delimičnog ili potpunog zatvaranja deonice puta zbog oštećenja na konstrukciji mosta. Simulacioni model u VISUM-u jednog dela nacionalne mreže Srbije korišćen je kao osnova za procenu ‘‘ranjivosti’’ linkova koji prelaze preko mostova ugroženih poplavama