VEHICLES FRONTAL IMPACT ANALYSIS USING COMPUTER SIMULATION AND CRASH TEST

Dragos Sorin Dima,Dinu Covaciu 한국자동차공학회 2019 International journal of automotive technology Vol.20 No.4

Reconstruction of car accidents is a complex task, with many unknown variables. Among the parameters used to assess the accident severity, in case of a frontal collision between two vehicles, are the change in velocity (delta-v) and the Energy Equivalent Speed (EES). The EES is usually determined based on the deformations. Delta-v can be obtained from the crash pulse recorded with Event Data Recorders, or with crash loggers based on accelerometers, in case of crash tests. In this paper is presented a full scale crash test that involves two vehicles in a frontal collision. The results are obtained using different analysis methods: direct application of a model, processing the measured crash pulse, and computer simulation.

Bile Acids and Intestinal Dysbiosis in Alcoholic Hepatitis

( Dragos Ciocan ),( Cosmin Sebastian Voican ),( Laura Wrzosek ),( Cindy Hugot ),( Gabriel Perlemuter ),( Anne-marie Cassard ) 대한간학회 2017 춘·추계 학술대회 (KASL) Vol.2017 No.1

Aims: Alcoholic liver disease is associated with dysbiosis, impaired gut barrier and inflammation. Intestinal microbiota (IM) plays an important role in bile acids (BA) homeostasis and impact the gut barrier and promotes inflammation. The aim of our study was to study the structure of the IM and its function in BA homeostasis in alcoholic patients according to the severity of alcoholic liver disease. Methods: We included in a prospective study 4 groups of active alcoholic patients (N=97): two non-cirrhotic (nc) without or with alcoholic hepatitis (AH) (noAHnc, N=54 or AHnc N=14, respectively) and two cirrhotic groups without or with AH (noAHc, N=16 or sAHc, N=13, respectively). Serum and fecal BA profiles, as well as IM composition, using high-throughput 16s sequencing, were assessed. Results: In sAHc patients compared to noAHc patients, there was an increase in serum total BA, primary BA (total CA and total CDCA), conjugated BA and tauro-glycoconjugated ratio and a decrease in the UDCA/total BA and secondary/primary ratio. In feces, there was a decrease in total BA and an increase in secondary BA (total LCA and DCA). These 2 groups had a different IM structure. At the phyla level, there was an increase in Actinobacteria and a decrease in Bacteroidetes; 7 genera were increased and 4 were decreased. Moreover, in sAHc patients compared to noAHc patients, there was an increase in 4 and a decrease in 11 metabolic pathways (eg increase in glutathion and nucleotid metabolism, phosphotransferase system). In AHnc patients as compared to noAHnc, there was an increase in serum total conjugated BA. The IM of AHnc patients was characterized by an increase in Wolbachia and Dorea as compared to noAHnc. Conclusions: Disruption of BA homeostasis associated with alcoholic hepatitis is correlated to a specific IM signature that may lead to liver disease progression.

Different Intestinal Microbiota Profile in Alcoholic Pancreatitis as Compared to Alcoholic Hepatitis

( Dragos Ciocan ),( Vinciane Rebours ),( Anne-marie Cassard ),( Laura Wrzosek ),( Cosmin Sebastian Voican ),( Virginie Puchois ),( Philippe Levy ),( Gabriel Perlemuter ) 대한간학회 2017 춘·추계 학술대회 (KASL) Vol.2017 No.1

Aims: Chronic excessive alcohol consumption may cause alcoholic liver disease (ALD) or alcoholic pancreatitis (AP) in only a subset of patients. We have shown that individual susceptibility to ALD is substantially driven by intestinal microbiota (IM). However, factors related to tissue predilection (liver or pancreas) to alcohol toxicity are unknown. We aimed to characterize the IM profile in alcoholic patients according to the presence and the nature of the complication ie severe alcoholic hepatitis (sAH) or AP. Methods: Eighty-two alcoholic patients were included into 3 groups according to their complications: AP (N=24), sAH (N=13) and no complication despite a similar amount of alcohol consumption (alcoholic controls, N=45). IM was analyzed using high-throughput sequencing of the 16S Ribosomal RNA (16S RNA) gene. Results: Patients with AP had a reduced bacterial diversity (p=0.001) and a different global microbial composition as compared to alcoholic controls (p=0.001). 17 taxa at the genus level were different between the 2 groups; among them, 8 were increased in AP (Klebsiella, Enterococcus, Aquabacterium and Sphingomonas). When compared to sAH there was no difference in bacterial diversity between the 2 groups. However, 16 taxa were increased in sAH and 10 in AP. After adjusting for confounding factors (age, sex, BMI, alcohol intake, diabetes and proton-pump inhibitors) there was a marked increase in Haemophilus in sAH patients. Conclusions: Patients with AP have a specific dysbiosis as compared to alcoholic controls. Specific microbiome signatures are associated with AP and sAH.

Evaluation of the new coastal protection scheme at Mamaia Bay in the nearshore of the Black Sea

Niculescu, Dragos M.,Rusu, Eugen V.C. Techno-Press 2018 Ocean systems engineering Vol.8 No.1

The target area of the proposed study, Mamaia beach, is a narrow stretch of sand barrier island that sits between the Siutghiol Lake and the Black Sea. In the northern part of the bay, is located the Midia Port, where between 1966 and 1971 a long extension of 5 km of the offshore was built. Because of this extension, the natural flow of sediments has been significantly changed. Thus, the southern part of the Mamaia Bay had less sand nourishment which meant that the coast was eroding and to prevent it a protection of six dikes was built. After approximately forty years of coastal erosion, the south of the Mamaia Bay had in 2016 a new protection scheme, which includes first of all the beach nourishment and a new dike structure (groins scheme for protection) to protect it. From this perspective, the objective of the proposed study is to evaluate the effectiveness of the old Master plan against the new one by modeling the outcome of the two scenarios and to perform a comparison with a third one, in which the protection dikes do not exist and only the artificial nourishment has been done. In order to assess the wave processes and the current patterns along the shoreline, a complex computational framework has been applied in the target area. This joins the SWAN spectral phase averaged model with the 1D surf model. Furthermore, new UAV technology was also used to map out, chart and validate the numerical model outputs within the target zone for a better evaluation of the trends expected in the shoreline dynamics.

Pharmacophore-based virtual screening.

Humana Press 2011 METHODS IN MOLECULAR BIOLOGY -CLIFTON THEN TOTOWA- Vol.672 No.-

<P>This chapter is a review of the most recent developments in the field of pharmacophore modeling, covering both methodology and application. Pharmacophore-based virtual screening is nowadays a mature technology, very well accepted in the medicinal chemistry laboratory. Nevertheless, like any empirical approach, it has specific limitations and efforts to improve the methodology are still ongoing. Fundamentally, the core idea of 'stripping' functional groups of their actual chemical nature in order to classify them into very few pharmacophore types, according to their dominant physico-chemical features, is both the main advantage and the main drawback of pharmacophore modeling. The advantage is the one of simplicity - the complex nature of noncovalent ligand binding interactions is rendered intuitive and comprehensible by the human mind. Although computers are much better suited for comparisons of pharmacophore patterns, a chemist's intuition is primarily scaffold-oriented. Its underlying simplifications render pharmacophore modeling unable to provide perfect predictions of ligand binding propensities - not even if all its subsisting technical problems would be solved. Each step in pharmacophore modeling and exploitation has specific drawbacks: from insufficient or inaccurate conformational sampling to ambiguities in pharmacophore typing (mainly due to uncertainty regarding the tautomeric/protonation status of compounds), to computer time limitations in complex molecular overlay calculations, and to the choice of inappropriate anchoring points in active sites when ligand cocrystals structures are not available. Yet, imperfections notwithstanding, the approach is accurate enough in order to be practically useful and actually is the most used virtual screening technique in medicinal chemistry - notably for 'scaffold hopping' approaches, allowing the discovery of new chemical classes carriers of a desired biological activity.</P>

Modelling of Iron Losses in Salient Pole Permanent Magnet Synchronous Motors

Valentin NAVRAPESCU,Dragos Ovidiu KISCK,George ANDRONESCU,Mircea POPESCU,Mariana KISCK 전력전자학회 2007 ICPE(ISPE)논문집 Vol.- No.-

Today, for the same rated power and speed electrical drives we have a strong competitor to the induction motors. This one it is represented by permanent magnet synchronous motors (PMSM) with salient pole rotors. In this paper are presented dedicated analytical and numerical models for the iron loss effect over the motor performance. It is presented a comprehensive comparison between no-load and loaded conditions test data for all the models presented.

Gateway Strategies for VoIP Traffic over Wireless Multihop Networks

( Kyungtae Kim ),( Dragos Niculescu ),( Sangjin Hong ) 한국인터넷정보학회 2011 KSII Transactions on Internet and Information Syst Vol.5 No.1

When supporting both voice and TCP in a wireless multihop network, there are two conflicting goals: to protect the VoIP traffic, and to completely utilize the remaining capacity for TCP. We investigate the interaction between these two popular categories of traffic and find that conventional solution approaches, such as enhanced TCP variants, priority queues, bandwidth limitation, and traffic shaping do not always achieve the goals. TCP and VoIP traffic do not easily coexist because of TCP aggressiveness and data burstiness, and the (self-) interference nature of multihop traffic. We found that enhanced TCP variants fail to coexist with VoIP in the wireless multihop scenarios. Surprisingly, even priority schemes, including those built into the MAC such as RTS/CTS or 802.11e generally cannot protect voice, as they do not account for the interference outside communication range. We present VAGP (Voice Adaptive Gateway Pacer) - an adaptive bandwidth control algorithm at the access gateway that dynamically paces wired-to-wireless TCP data flows based on VoIP traffic status. VAGP continuously monitors the quality of VoIP flows at the gateway and controls the bandwidth used by TCP flows before entering the wireless multihop. To also maintain utilization and TCP performance, VAGP employs TCP specific mechanisms that suppress certain retransmissions across the wireless multihop. Compared to previous proposals for improving TCP over wireless multihop, we show that VAGP retains the end-to-end semantics of TCP, does not require modifications of endpoints, and works in a variety of conditions: different TCP variants, multiple flows, and internet delays, different patterns of interference, different multihop topologies, and different traffic patterns.

On the derived categories of degree d hypersurface fibrations

Ballard, Matthew,Deliu, Dragos,Favero, David,Isik, M. Umut,Katzarkov, Ludmil Springer-Verlag 2018 Mathematische Annalen Vol.371 No.1

Microbiota, a key player in alcoholic liver disease

Anne-Marie Cassard,Dragos Ciocan 대한간학회 2018 Clinical and Molecular Hepatology(대한간학회지) Vol.24 No.2

Alcoholic liver disease (ALD) is a major cause of morbidity and mortality worldwide. Only 20% of heavy alcohol consumers develop alcoholic liver cirrhosis. The intestinal microbiota (IM) has been recently identified as a key player in the severity of liver injury in ALD. Common features of ALD include a decrease of gut epithelial tight junction protein expression, mucin production, and antimicrobial peptide levels. This disruption of the gut barrier, which is a prerequisite for ALD, leads to the passage of bacterial products into the blood stream (endotoxemia). Moreover, metabolites produced by bacteria, such as short chain fatty acids, volatile organic compounds (VOS), and bile acids (BA), are involved in ALD pathology. Probiotic treatment, IM transplantation, or the consumption of dietary fiber, such as pectin, which all alter the ratio of bacterial species, have been shown to improve liver injury in animal models of ALD and to be associated with an improvement in gut barrier function. Although the connections between the microbiota and the host in ALD are well established, the underlying mechanisms are still an active area of research. Targeting the microbiome through the use of prebiotic, probiotic, and postbiotic modalities could be an attractive new approach to manage ALD.

A Study on Sensorless Control of Transverse Flux Rotating Motor Based on MRAS with Parameter Estimation

Jiwon Kim,Kwangwoon Kim,Dragos Ovidiu Kisck,Dohyun Kang,Junghwan Chang,Jangmok Kim 전력전자학회 2011 JOURNAL OF POWER ELECTRONICS Vol.11 No.6

This paper presents a sensorless control and parameter estimation strategies for a Transverse Flux Rotating Motor (TFRM). The proposed sensorless control method is based on a Model Reference Adaptive System (MRAS) to estimate the stator flux. Parameter estimation theory is also applied into the sensorless control method to estimate motor parameters, such as inductances. The effectiveness of the proposed methods is verified by some simulations and experiments.