Diego Lopez G - Academia.edu (original) (raw)

Papers by Diego Lopez G

This paper discusses the design and performance of the time measurement technique and of the sync... more This paper discusses the design and performance of the time measurement technique and of the synchronization systems of the CMS hadron calorimeter. Time measurement performance results are presented from test beam data taken in the years 2004 and 2006. For hadronic showers of energy greater than 100 GeV, the timing resolution is measured to be about 1.2 ns. Time synchronization and out-of-time background rejection results are presented from the Cosmic Run At Four Tesla and LHC beam runs taken in the Autumn of 2008. The inter-channel synchronization is measured to be within ±2 ns.

Achieving blind people autonomous shopping in a supermarket is a real challenge. Without help fro... more Achieving blind people autonomous shopping in a supermarket is a real challenge. Without help from another person is very hard or impossible for them to reach to a specific supermarket section and browse through its products. Besides, once there, they cannot identify the products and their features (e.g. price, brand and due date) to decide whether they want to buy them or not. This work presents BlindShopping, an RFID and QR-code based mobile solution to enable accessible shopping for blind people, only demanding inexpensive off-the-shelf technology and limiting the deployment effort from the supermarket.

European Physical Journal C, 2011

Jet cross sections have been measured for the first time in proton-proton collisions at a centre-... more Jet cross sections have been measured for the first time in proton-proton collisions at a centre-of-mass energy of 7 TeV using the ATLAS detector. The measurement uses an integrated luminosity of 17 nb−1 recorded at the Large Hadron Collider. The anti-k t algorithm is used to identify jets, with two jet resolution parameters, R=0.4 and 0.6. The dominant uncertainty comes from the jet energy scale, which is determined to within 7% for central jets above 60 GeV transverse momentum. Inclusive single-jet differential cross sections are presented as functions of jet transverse momentum and rapidity. Dijet cross sections are presented as functions of dijet mass and the angular variable χ. The results are compared to expectations based on next-to-leading-order QCD, which agree with the data, providing a validation of the theory in a new kinematic regime.

European Physical Journal C, 2010

The ATLAS detector at the Large Hadron Collider has collected several hundred million cosmic ray ... more The ATLAS detector at the Large Hadron Collider has collected several hundred million cosmic ray events during 2008 and 2009. These data were used to commission the Muon Spectrometer and to study the performance of the trigger and tracking chambers, their alignment, the detector control system, the data acquisition and the analysis programs. We present the performance in the relevant parameters that determine the quality of the muon measurement. We discuss the single element efficiency, resolution and noise rates, the calibration method of the detector response and of the alignment system, the track reconstruction efficiency and the momentum measurement. The results show that the detector is close to the design performance and that the Muon Spectrometer is ready to detect muons produced in high energy proton–proton collisions.

A large sample of cosmic ray events collected by the CMS detector is exploited to measure the spe... more A large sample of cosmic ray events collected by the CMS detector is exploited to measure the specific energy loss of muons in the lead tungstate (PbWO 4 ) of the electromagnetic calorimeter. The measurement spans a momentum range from 5 GeV/c to 1 TeV/c. The results are consistent with the expectations over the entire range. The calorimeter energy scale, set with 120 GeV/c electrons, is validated down to the sub-GeV region using energy deposits, of order 100 MeV, associated with low-momentum muons. The muon critical energy in PbWO 4 is measured to be 160 +5 −6 ± 8 GeV, in agreement with expectations. This is the first experimental determination of muon critical energy.

Studia Geophysica Et Geodaetica, 2010

In this work we have assessed the hybrid algorithm of NeuroFuzzy logic (NFL), to establish a corr... more In this work we have assessed the hybrid algorithm of NeuroFuzzy logic (NFL), to establish a correlation between global climatic changes (benthic foraminiferal δ18O data), experimental S-ratio (factor characterizing stability of remanent magnetization) and magnetic susceptibility (κ). Magnetic proxies have been measured in 44 samples of the Colombian stratigraphic well Saltarín 1A (distal Llanos foreland basin). κ and Sratios were linked to global δ18O data assuming a constant accumulation rate for a 305 meters thick stratigraphic interval flanked by the two palynological age constrains available. This interval encompasses, from top to base, the bottom of the Guayabo formation, the León, and the upper unit of the Carbonera formations (lower to middle Miocene). The best inference is accomplished applying a Takagi-Sugeno-Kan (TSK) fuzzy model with four fuzzy rules and the δ18O, S-ratios and κ data used in a linear form to train the system. These results are interpreted as the outcome of a significant influence of global climatic changes upon magnetic proxies. A stronger correlation is perhaps prevented by the likely influence of local and regional tectonic events and climatic changes that could have affected the distal segment of the Colombian Llanos foreland basin during Miocene times. We argue that late diagenesis of primary magnetic minerals and the assumption of a constant accumulation rate might have a minor influence on these results.

Journal of Bridge Engineering, 2008

This paper presents the development and experimental validation of a multizard bridge pier concep... more This paper presents the development and experimental validation of a multizard bridge pier concept, i.e., a bridge pier system capable of providing an adequate level of protection against collapse under seismic and blast loading ͑but not acting simultaneously͒. A multicolumn pier-bent with concrete-filled steel tube ͑CFST͒ columns is the proposed concept, and the adequacy of this system is experimentally investigated under blast loading. This paper describes simplified blast analysis, multihazard design of bridge piers, and blast experimental program and results. Additionally, the results from the blast experiments are compared with the results from the simplified method of analysis considering an equivalent single degree of freedom system having an elastic-perfectly plastic behavior. It is found that prototype bridge CFST columns can be designed to provide both satisfactory seismic performance and adequate blast resistance. It is also shown that the CFST columns exhibited a ductile behavior under blast load in a series of tests at 1 / 4 scale. Maximum deformation of the columns could be calculated using simplified analysis considering a factor to account for the reduction of pressures on the circular column and determined from this experimental program.

Journal of Vascular Surgery, 2007

Popliteal artery entrapment syndrome is recognized as a cause of claudication and arterial occlus... more Popliteal artery entrapment syndrome is recognized as a cause of claudication and arterial occlusion in young patients. Aneurysmal degeneration is a reported but rare complication. We present the case of a young male patient with large bilateral popliteal aneurysms due to symptomatic anatomic entrapment. The left aneurysm was acutely thrombosed, and urgent bypass surgery was required. The contralateral aneurysm was resected by a posterior approach and replaced with an autologous vein graft. Type IV popliteal entrapment by a fibrous band independent of the gastrocnemius muscle was diagnosed during surgery and divided. Early detection of popliteal entrapment is highly important to prevent the development of this serious complication. ( J Vasc Surg 2007;46:1047-50.)

This paper discusses the design and performance of the time measurement technique and of the sync... more This paper discusses the design and performance of the time measurement technique and of the synchronization systems of the CMS hadron calorimeter. Time measurement performance results are presented from test beam data taken in the years 2004 and 2006. For hadronic showers of energy greater than 100 GeV, the timing resolution is measured to be about 1.2 ns. Time synchronization and out-of-time background rejection results are presented from the Cosmic Run At Four Tesla and LHC beam runs taken in the Autumn of 2008. The inter-channel synchronization is measured to be within ±2 ns.

Achieving blind people autonomous shopping in a supermarket is a real challenge. Without help fro... more Achieving blind people autonomous shopping in a supermarket is a real challenge. Without help from another person is very hard or impossible for them to reach to a specific supermarket section and browse through its products. Besides, once there, they cannot identify the products and their features (e.g. price, brand and due date) to decide whether they want to buy them or not. This work presents BlindShopping, an RFID and QR-code based mobile solution to enable accessible shopping for blind people, only demanding inexpensive off-the-shelf technology and limiting the deployment effort from the supermarket.

European Physical Journal C, 2011

Jet cross sections have been measured for the first time in proton-proton collisions at a centre-... more Jet cross sections have been measured for the first time in proton-proton collisions at a centre-of-mass energy of 7 TeV using the ATLAS detector. The measurement uses an integrated luminosity of 17 nb−1 recorded at the Large Hadron Collider. The anti-k t algorithm is used to identify jets, with two jet resolution parameters, R=0.4 and 0.6. The dominant uncertainty comes from the jet energy scale, which is determined to within 7% for central jets above 60 GeV transverse momentum. Inclusive single-jet differential cross sections are presented as functions of jet transverse momentum and rapidity. Dijet cross sections are presented as functions of dijet mass and the angular variable χ. The results are compared to expectations based on next-to-leading-order QCD, which agree with the data, providing a validation of the theory in a new kinematic regime.

European Physical Journal C, 2010

The ATLAS detector at the Large Hadron Collider has collected several hundred million cosmic ray ... more The ATLAS detector at the Large Hadron Collider has collected several hundred million cosmic ray events during 2008 and 2009. These data were used to commission the Muon Spectrometer and to study the performance of the trigger and tracking chambers, their alignment, the detector control system, the data acquisition and the analysis programs. We present the performance in the relevant parameters that determine the quality of the muon measurement. We discuss the single element efficiency, resolution and noise rates, the calibration method of the detector response and of the alignment system, the track reconstruction efficiency and the momentum measurement. The results show that the detector is close to the design performance and that the Muon Spectrometer is ready to detect muons produced in high energy proton–proton collisions.

A large sample of cosmic ray events collected by the CMS detector is exploited to measure the spe... more A large sample of cosmic ray events collected by the CMS detector is exploited to measure the specific energy loss of muons in the lead tungstate (PbWO 4 ) of the electromagnetic calorimeter. The measurement spans a momentum range from 5 GeV/c to 1 TeV/c. The results are consistent with the expectations over the entire range. The calorimeter energy scale, set with 120 GeV/c electrons, is validated down to the sub-GeV region using energy deposits, of order 100 MeV, associated with low-momentum muons. The muon critical energy in PbWO 4 is measured to be 160 +5 −6 ± 8 GeV, in agreement with expectations. This is the first experimental determination of muon critical energy.

Studia Geophysica Et Geodaetica, 2010

In this work we have assessed the hybrid algorithm of NeuroFuzzy logic (NFL), to establish a corr... more In this work we have assessed the hybrid algorithm of NeuroFuzzy logic (NFL), to establish a correlation between global climatic changes (benthic foraminiferal δ18O data), experimental S-ratio (factor characterizing stability of remanent magnetization) and magnetic susceptibility (κ). Magnetic proxies have been measured in 44 samples of the Colombian stratigraphic well Saltarín 1A (distal Llanos foreland basin). κ and Sratios were linked to global δ18O data assuming a constant accumulation rate for a 305 meters thick stratigraphic interval flanked by the two palynological age constrains available. This interval encompasses, from top to base, the bottom of the Guayabo formation, the León, and the upper unit of the Carbonera formations (lower to middle Miocene). The best inference is accomplished applying a Takagi-Sugeno-Kan (TSK) fuzzy model with four fuzzy rules and the δ18O, S-ratios and κ data used in a linear form to train the system. These results are interpreted as the outcome of a significant influence of global climatic changes upon magnetic proxies. A stronger correlation is perhaps prevented by the likely influence of local and regional tectonic events and climatic changes that could have affected the distal segment of the Colombian Llanos foreland basin during Miocene times. We argue that late diagenesis of primary magnetic minerals and the assumption of a constant accumulation rate might have a minor influence on these results.

Journal of Bridge Engineering, 2008

This paper presents the development and experimental validation of a multizard bridge pier concep... more This paper presents the development and experimental validation of a multizard bridge pier concept, i.e., a bridge pier system capable of providing an adequate level of protection against collapse under seismic and blast loading ͑but not acting simultaneously͒. A multicolumn pier-bent with concrete-filled steel tube ͑CFST͒ columns is the proposed concept, and the adequacy of this system is experimentally investigated under blast loading. This paper describes simplified blast analysis, multihazard design of bridge piers, and blast experimental program and results. Additionally, the results from the blast experiments are compared with the results from the simplified method of analysis considering an equivalent single degree of freedom system having an elastic-perfectly plastic behavior. It is found that prototype bridge CFST columns can be designed to provide both satisfactory seismic performance and adequate blast resistance. It is also shown that the CFST columns exhibited a ductile behavior under blast load in a series of tests at 1 / 4 scale. Maximum deformation of the columns could be calculated using simplified analysis considering a factor to account for the reduction of pressures on the circular column and determined from this experimental program.

Journal of Vascular Surgery, 2007

Popliteal artery entrapment syndrome is recognized as a cause of claudication and arterial occlus... more Popliteal artery entrapment syndrome is recognized as a cause of claudication and arterial occlusion in young patients. Aneurysmal degeneration is a reported but rare complication. We present the case of a young male patient with large bilateral popliteal aneurysms due to symptomatic anatomic entrapment. The left aneurysm was acutely thrombosed, and urgent bypass surgery was required. The contralateral aneurysm was resected by a posterior approach and replaced with an autologous vein graft. Type IV popliteal entrapment by a fibrous band independent of the gastrocnemius muscle was diagnosed during surgery and divided. Early detection of popliteal entrapment is highly important to prevent the development of this serious complication. ( J Vasc Surg 2007;46:1047-50.)