bluuebunny/crossref_metadata_2025 huggingface dataset:
ORTAOKUL ÖĞRENCİLERİNİN YAZMA BECERİLERİ, YAZMAYA YÖNELİK TUTUMLARI VE YAZMA MOTİVASYONLARI ARASINDAKİ İLİŞKİ
Authors: TÜRKBEN Tuncay
Published: September 2021

Bu araştırma, ortaokul 6, 7 ve 8. sınıf öğrencilerinin yazma tutumları, yazma motivasyonları ve yazma becerileri arasındaki ilişkiyi ve öğrencilerin yazmaya ilişkin tutum ve motivasyonlarının yazma başarısını ne oranda yordadığını belirlemek amacıyla gerçekleştirilmiştir. Araştırma, ilişkisel tarama modeline göre yürütülmüştür. Araştırmanın evrenini 2019-2020 eğitim öğretim yılında Aksaray ilinde öğrenim gören ortaokul öğrencilerinin tamamı, örneklemini ise basit seçkisiz örnekleme yöntemiyle seçilen 450 öğrenci oluşturmaktadır. Öğrencilerin yazma becerilerini değerlendirmek için Sezer (2005) tarafından geliştirilen rubrik kullanılmıştır. Araştırmada, ortaokul öğrencilerinin yazma tutumlarını belirlemek amacıyla Can ve Topçuoğlu Ünal (2017) tarafından geliştirilen Yazma Tutum Ölçeği, yazma motivasyonlarını belirlemek için de Yaman vd. (2016) tarafından geliştirilen Yazma Motivasyonu Ölçeği kullanılmıştır. Araştırma sonunda, öğrencilerin yazılı anlatım becerilerinin orta düzeyde olduğu, kız ve erkek öğrencilerin yazma puanları arasında kız öğrencilerin lehine anlamlı farklılıklar olduğu tespit edilmiştir. Araştırma bulgularına göre baba eğitim düzeyi arttıkça öğrencilerin yazma puanları da istatistiksel olarak artmaktadır. Günlük tutma alışkanlığı ise öğrencilerin yazma becerilerini olumlu yönde etkilemektedir. Yazma becerileri, yazmaya yönelik tutum ve yazma motivasyonu puanları arasındaki korelasyon katsayıları incelendiğinde ise en yüksek ilişkinin yazmaya yönelik tutum puanları ile yazma motivasyonu puanları arasında, en düşük ilişkinin yazma becerileri puanları ile yazma motivasyonu puanları arasında olduğu görülmektedir. Ayrıca üç ölçek arasındaki korelasyon değerleri pozitif yönde anlamlı sonuçlar vermektedir.
ORTAOKUL MATEMATİK ÖĞRETMENLERİNİN REFORM PROGRAMLARINA İLİŞKİN ALGILARI
Authors: BOZKURT Erhan , KÜÇÜKAKIN Gonca , ÖKSÜZ Hava
Published: September 2021

Bu fenomenoloji araştırmasında, ortaokul matematik öğretmenlerinin öğretim programı olgusuna ve Türkiye’de matematik eğitimi alanında son yıllarda uygulanmakta olan yeni öğretim programlarına ilişkin algılarının tanımlanması amaçlanmıştır. Araştırmaya Türkiye’deki bir ilin devlet okullarında görev yapmakta olan 12 ortaokul matematik öğretmeni dâhil edilmiştir. Araştırmada veriler yarı yapılandırılmış görüşmeler aracılığıyla elde edilmiştir. Görüşmelerden elde edilen veriler içerik analizi yöntemiyle analiz edilmiştir. Araştırmadan elde edilen bulgular ortaokul matematik öğretmenlerinin genel anlamda öğretim programı olgusunun mesleki yaşamlarındaki rolü ve önemine ilişkin farkındalıklarının düşük olduğuna işaret etmektedir. Buna karşın ideal matematik öğretim programı algılarının reform programlarında ortaya konulan yeniliklerle uyumlu olduğu tespit edilmiştir. Dolayısıyla öğretmenlerin reform programlarının gerekliliğine ve önemine inandıkları söylenebilir. Ancak bu araştırmada öğretmenler matematik reform programlarının uygulanabilirliğine yönelik olumsuz duygu ve değerlendirmeler ortaya koymuşlardır. Matematik reform programlarını, test başarısı odaklı ölçme-değerlendirme sistemiyle uyumsuz olması ve sık değişmesi gibi çeşitli nedenlerle değersiz, güvenilmez ve kaygı verici olarak nitelendirmişlerdir. Bu çelişkili bulgular, ortaokul matematik öğretmenlerinin öğretim programı bilgilerindeki eksikliğe işaret etmektedir.
THE USING OF TERRESTRIAL LASER (POINT CLOUD) SCANNING TECHNOLOGIES ON URBAN SCALE: EXAMPLE OF THE HISTORICAL URBAN TEXTURE OF LAPSEKİ
Authors: ZAĞRA Hatice Çiğdem , ÖZDEN Sibel
Published: September 2021

Aim: This study aims to comparatively evaluate the use potential of orthophoto images obtained by terrestrial laser scanning technologies on an urban scale through the "Old Lapseki Finds Life Project" prepared using terrestrial laser scanning technologies and the "Enez Historical City Square Project" prepared using traditional methods. Method: In the study, street improvement projects of 29.210 m2 Lapseki and 29.214 m2 Enez city designed on an urban scale were evaluated and compared with descriptive statistics based on different parameters. Results: In the study, it has been determined that terrestrial laser (point cloud) technologies are 99,9% accurate when compared to traditional methods, save time by 83,08% and reduce workforce by 80%. In addition, it has been determined that terrestrial laser scanning technologies accelerate project processes compared to traditional methods. Conclusion: In this study, the use of laser scanning technologies, which are basically reverse engineering applications, in architectural restoration projects, determination of the current situation and damage, architectural documentation of structures and preparation of three-dimensional models, in terms of efficiency in survey studies are evaluated. It has been observed that orthophoto images obtained by terrestrial laser scanning technologies in architectural relief-restoration-restitution projects have potentials' worth using in different stages of the project.
THE DIFFUSION-DRIFT PROCESS WITH ACCOUNT HEATING AND RECOMBINATION IN THE p-i-n DIODES ACTIVE REGION MATHEMATICAL MODELING BY THE PERTURBATION THEORY METHODS
Authors: Bomba A. Ya. , Moroz I. P.
Published: September 2021

With prolonged transmission of an electric current through the semiconductor devices, in a particular p-i-n diodes, an electron-hole plasma of their active region is heated. This paper presents the theoretical studies results of the plasma heating effect by the Joule heat release in the p-i-n diode volume and the charge carriers recombination energy release on the plasma concentration distribution in the p-i-n diodes active region. The mathematical model is proposed for predicting the electron-hole plasma stationary concentration distribution and the temperature field in the i-region of the bulk p-i-n diodes in the form of a nonlinear boundary value problem in a given area for the equations system, which consist of the charge carrier current continuity equations, the Poisson and the thermal conductivity. It is shown that the differential equations of the model contain a small parameter in such a way that the Poisson equation is singularly perturbed and the heat conduction equation is regularly perturbed. An approximate solution of the problem posed is obtained in the form of the corresponding asymptotic series in powers of the small parameter. The asymptotic serieses, which describes the behavior of the plasma concentration and potential in the investigated region, containing near-boundary corrections to ensure the fulfillment of the boundary conditions. The terms of these series are found as a result of solving a sequence of boundary value problems, obtained as a result of splitting the original problem, for systems of linear differential equations. The boundary value problem for a nonlinear heat equation is reduced to a sequence of problems for the corresponding linear inhomogeneous equations. The process of refining solutions is iterative. The stabilization of the process is ensured by the existence of negative feedback in the system (as the temperature rises, the mobility of charge carriers decreases).
DIMPLE GENERATOR OF VORTEX STRUCTURES
Authors: Voskobijnyk A. V. , Turick V. M. , Voskoboinyk O. A. , Voskoboinick V. A.
Published: September 2021

The paper presents the results of experimental studies of the space-time characteristics of the velocity and pressure field inside a hemispherical dimple on a flat surface. The features of the formation and development of vortex structures generated inside the dimple, as well as their interaction with the streamlined surface of the dimple and the boundary layer were established. Integral, spectral and correlation characteristics of the field of velocity, dynamic and wall pressure fluctuations were obtained. The velocities and directions of transfer of large-scale vortex structures and small-scale vortices inside the dimple were determined. The frequencies of rotations and ejections of large-scale vortices, the frequencies of oscillations of the vortex flow inside the dimple and self-oscillations of the vortex structures of the shear layer, their subharmonics and harmonics of higher orders were established.
POZİTİF PSİKOLOJİK SERMAYENİN İŞ TATMİNİ ÜZERİNDEKİ DOĞRUSAL VE DOĞRUSAL OLMAYAN ETKİLERİ: ÖZEL EĞİTİM ÇALIŞANLARINA YÖNELİK BİR ARAŞTIRMA
Authors: Yıldırım Ahmet
Published: September 2021

Pozitif psikolojik sermaye, bireyin güçlü yönlerini konu alan, kapasitesini yükseltmeyi, potansiyelini ortaya çıkarmayı öngören ve örgütsel etkinliği arttırmak için bireyin pozitif yönlerin güçlendirilmesi gerektiğini vurgulayan bir içeriğe sahiptir. Öte yandan insan kaynağının örgütler açısından önemine bağlı olarak çalışanların iş tatmin düzeyleri giderek önem kazanmaktadır. Çalışanlar açısından ise, iş tatmini birçok etkinin baskısı altındadır. Bu çalışmada çalışanların pozitif psikolojik sermayelerinin iş tatmini üzerindeki doğrusal ve doğrusal olmayan etkilerini inceleyerek çalışanın iş tatmini etkileyen faktörlerin sınıflandırmasını amaçlanmaktadır.
Bu amaç doğrultusunda Muğla ili Özel Eğitim Rehabilitasyon merkezlerinde çalışan 192 özel eğitim çalışanın tamamına gönderilen anket formlarından geri dönen yeterli ve veri anlamlılığına sahip formlardan 152’si araştırmaya dâhil edilmiştir.
Elde edilen veriler birinci düzey çok faktörlü doğrulayıcı faktör analizi (DFA) sonucu pozitif psikolojik sermaye ölçeğinin umut, dayanıklılık ve iyimserlik boyutları iş tatminini belirleyen başlıca faktörler olarak tespit edilmiştir. Pozitif psikolojik sermaye ölçeğinin özyeterlilik boyutunun anlamsız çıkmasından dolayı özyeterlilik boyutu değerlendirmeye alınmamıştır. İş tatmini ölçeği ise tek boyut üzerinden değerlendirmeye alınmıştır. Çalışmada özel eğitim çalışanlarının pozitif psikolojik sermayeye düzeyleri ile iş tatmin seviyeleri arasındaki doğrusal olmayan etkiyi test etmek için kukla değişkenli regresyon analizi yardımıyla ceza-ödül karşıtlığı analizi gerçekleştirilmiştir. Bu analiz neticesi pozitif psikolojik sermayenin umut, esneklik ve iyimserlik boyutları iş tatmini üzerinde güdüleyici faktör olarak tespit edilmiştir.
Eklemeli İmalat Yöntemi ile Optimum Düz Dişli Çark Tasarımı ve Üretimi
Authors: DOĞAN Oğuz , KAMER Muhammed Safa
Published: September 2021

Dişli çarklar endüstride en çok kullanılan güç aktarma organı olarak karşımıza çıkmaktadır. Güç aktarımının olduğu hemen her yerde ilk sırada kullandıklarından dolayı, üzerlerinde bulundukları makinelerin toplam ağırlıklarını önemli ölçüde arttırmaktadırlar. Bu nedenle dişli geometrisi üzerinde gerçekleştirilecek hafifletme çalışmaları ile birlikte daha hafif ve sürdürülebilir makine tasarımları gerçekleştirilebilecektir. Bu çalışmada, eklemeli imalat yöntemi ve topoloji optimizasyonu yöntemleri kullanılarak, hafif yenilikçi ve sürdürülebilir bir dişli çark tasarımı gerçekleştirilmiştir. Bu amaçla öncelikle standart bir dişli geometrisi oluşturulmuştur. Ardından standart dişli çarka topoloji optimizasyonu uygulanarak optimum malzeme dağılımı belirlenmiştir. Elde edilen malzeme dağılımı, üretilebilirlik ve mukavemet kısıtları dikkate alınarak yeni bir dişli çark tasarımı yapılmıştır. Tasarlanan yeni ve standart dişliye birim yükler uygulanarak, dişli çarkların mukavemet performansları test edilmiş ve karşılaştırılmıştır. Ardından tasarlanan standart ve optimize edilmiş dişli çarklar üç boyutlu yazdırma yöntemi ile üretilmiş ve kütle değişimleri ölçülmüştür. Sonuç olarak, standart dişli çarka göre % 30 oranında hafifletme sağlanırken, gerilme değerlerinde ise %15’ lik bir artış gözlemlenmiştir.
Tungsten Karbür Besleme Stoğundan Elde Edilen Parçalar İçin İdeal Çözücünün Araştırılması
Authors: SAMET Kamran , SUBAŞI Mehmet , KARATAŞ Çetin
Published: September 2021

Bu çalışmada tungsten karbür - kobalt (WC-Co) besleme stoğundan Toz Enjeksiyon Kalıplama (TEK) yöntemi ile elde edilmiş numunelerin kimyasal bağlayıcı aşamasında kullanılacak çözücü türü araştırılmıştır. TEK yöntemi ile WC-Co besleme stoğundan hazırlanan deney numunelerinin kimyasal bağlayıcı giderme deneyleri onüç farklı çözücü (Toluen, Benzen, Heptan, Aseton, Etanol, Karbon tetraklorür (CCl4), Etanol+ Karbon tetraklorür (CCl4), Metanol, Nitrik asit, Hidroklorik asit, Sülfürik asit, Kloroform, Dikloroetan) kullanılarak gerçekleştirilmiştir. Deneyler sonucunda WC-Co besleme stoğu için bulunabilirlik ve maliyet açısından en ideal çözücünün etanol olduğu belirlenmiştir. Ayrıca deneyler sonucunda 60 °C sıcaklık ve 60 saat sürede etanol içerisinde tutulan parçalarda hedeflenen sonuçların elde edildiği belirlenmiştir.
Teleseismic source parameters and rupture characteristics of the 24 November 1987, Superstition Hills earthquake
Authors: Hwang Lorraine J. , Magistrale Harold , Kanamori Hiroo
Published: September 2021

Long-period body waves from the 24 November 1987, Superstition Hills earthquake are studied to determine the focal mechanism and spatial extent of the seismic source. The earthquake is a complex event consisting of two spatially distinct subevents with different focal mechanisms. Two consistent models of rupture are developed. For both models, the second subevent begins 8 sec after the initiation of the first subevent and the preferred centroid depth lies between 4 to 8 km. Model 1 consists of two point sources separated by 15 to 20 km along strike of the Superstition Hills fault. Model 2 consists of one point source and one line source with a rupture velocity of 2.5 km/sec with moment release distributed along strike of the focal plane at a distance of 10 to 22 km from the epicenter. These moment release patterns show that a significant amount of long-period energy is radiated from the southern segment of the fault. Total moment release for both models is approximately 8 × 1025 dyne-cm. Both models also suggest a change of dip from near vertical near the epicenter to steeply southwesterly dipping along the southern segment of the fault. The difference in rupture characteristics and fault dips seen teleseismically is also reflected in aftershock and afterslip data, and crustal structure underlying the two fault segments. The northern segment had more aftershocks and a smaller proportion of afterslip than the southern segment. The boundary between the two segments lies at a step in the basement that separates a deeper metasedimentary basement to the south from a shallower crystalline basement to the north.
Guided-wave tracking in 3-D: A tool for interpreting complex regional seismograms
Authors: Kennett B. L. N. , Bostock M. G. , Xie J.-K.
Published: September 2021

The tracking of guided-wave trains by raytracing in 3-D structures can provide a means of interpreting complex seismograms at regional distances. The method relies on the interpretation of Lg as the constructive interference of multiple S reflections within the crust, and strong scattering can be simulated by the inclusion of secondary sources.

This approach has been applied to Californian events observed in the southwestern United States whose records at regional distances frequently exhibit an extended and complex Lg coda with significant late energy arriving with group velocities of 2.5 km/sec or less. The general character of this energy precludes an interpretation as the result of stochastic scattering processes or dispersion in low velocity surface sediments; therefore some alternative explanation needs to be sought.

The observed wavetrains of events from two sites in southwestern California (Coalinga and North Baja) at stations LAC, MNV, and ELK have been compared with the predictions from tracking guided-wave patterns. Multipathing of energy by major changes in the thickness of the crustal wave guide is consistent with the extended and often “pulse-like” nature of the Lg coda. Examples of plausible multipathing mechanisms include reflection from the ocean-continent transition, scattering associated with topographic features such as the Sierra Nevada, and resonance within the narrow corridor of Baja California.
Seismic radiation from anSHline source in a laterally heterogeneous planar fault zone
Authors: Ben-Zion Yehuda , Aki Keiiti
Published: September 2021

A solution to the class of problems in which an SH line source is operating in a medium consisting of two quarter spaces with an arbitrary number of semi infinite vertical layers in between is given in a frequency-wavenumber domain. The general result is applied to a model with a single vertical layer, and synthetic seismograms are calculated for a source specified as an SH line dislocation at the interface between the vertical layer and the faster quarter space. The numerical examples demonstrate that moderate fault-normal material heterogeneity can have significant effects on the seismic response of a medium. The overall distribution of travel times, amplitudes, and motion polarities in the presence of fault zone material heterogeneity is different from a corresponding distribution in a homogeneous half space. The effects are most prominent near the fault zone, where head waves, surface waves, and trapped modes result in waveform complexities, large amplifications (over an order of magnitude in the fault zone itself), and first-motion polarities which are reversed from homogeneous medium predictions. The results imply that material heterogeneity should be included in fault zone models which are used for the interpretation of observed seismic data and theoretical calculations of near fault responses. Such models can be utilized to obtain important fault zone and earthquake source parameters.
Interpretation of physical status of arrival picks for microseismic source location
Authors: Ge Maochen , Kaiser P. K.
Published: September 2021

The automatic recognition of a microseismic event usually relies on two criteria: threshold voltage level and event recognition time window. Current microseismic source location techniques are severaly limited because the physical status of an arrival pick is not known. This paper presents a theory for the identification of the physical status of an arrival pick. It consists of an arrival time difference analysis and a residual analysis. The theory can be used to discriminate various types of arrival picks critical for microseismic source location. An event-based velocity model can then be established and used to determine the source location more accurately. The theory provides a unique approach that may be utilized in various automatic acoustic/seismic processing systems.
Event detection and location performance of the FINESA array in Finland
Authors: Uski Marja
Published: September 2021

The experimental seismic array FINESA in Finland is designed to monitor weak seismic events at regional and teleseismic distances. The array geometry currently comprises 15 short-period vertical seismometers in three concentric rings (A-, B-, and C-rings), with a diameter of the outer ring of about 2 km. In late 1989, the data acquisition system of the array was completely modernized. Signals are now transferred continuously via high-speed telephone lines to the processing centers at the Institute of Seismology in Helsinki and NORSAR in Norway, therefore allowing automatic real-time processing of the recorded data.

In this paper, the detection performance of the array in the current configuration has been evaluated. The results are encouraging: during a 2-week test period, FINESA detected at least one P and one S phase for 84 per cent of the events reported in the regional bulletin of the University of Helsinki, and 99 per cent of the events in the weekly teleseismic bulletins. Many additional events at both distance ranges were also found.

The estimated phase velocities obtained by the broadband frequency-wave-number analysis confidently identify the phase type (teleseismic Pgional PgionalS). However, the resolution of the analysis is not sufficient to separate Pg from Pn and Lg from Sn. The estimated backazimuths are reliable for phase association, the standard deviation of the estimates being 7° for regional P phases, 6° for regional S phases, and 23° for teleseismic P phases.

Finally, preliminary results from FINESA's on-line event location capability showed that the average error in the location estimates is 21 per cent of the true epicentral distance. The greatest error sources are uncertainty in the estimated azimuths and occasional misidentification of secondary phases (Lg, Sn and Rg). The error could be reduced by constructing a regional correction term for the azimuth estimates and “tuning” the phase identification algorithms for FINESA. The characteristics of the Rg-phase need to be especially considered.
Microseismicity and tectonics in northeast India
Authors: Kayal J. R. , De Reena
Published: September 2021

Three microearthquake surveys were carried out in Shillong Plateau, Mikir Hills, and Assam valley areas during 1984 to 1986. Some 422 events are relocated by the Homogeneous Station Method. The microseismicity map reveals intense crustal (10 to 40 km) activity beneath the Tura area of Shillong Plateau. The areas to the west of Shillong and the area around Mikir Hills also show high activity. The microseismicity map further shows major tectonic lineaments that are compatible with the Landsat Imagery lineaments and the major faults. Composite focal mechanisms of the microearthquakes show spatial variation of the tectonic stresses in the region. An ENE-WSW horizontal compressive stress is dominant in the Tura area, whereas a SE-NW horizontal compressive stress is dominant in the Shillong and Mikir Hills areas.
Performance of the short-period geophones of the IRIS/PASSCAL Array
Authors: Menke William , Shengold Larry , Hongsheng Guo , Ge Hu , Lerner-Lam Arthur
Published: September 2021

We calibrated 64 Mark Products L22-D short-period geophones of the IRIS/PASSCAL Array using a mass-displacement test. The mean natural frequency of the 192 components was 2.1 Hz (slightly larger than the nominal value of 2 Hz) with a standard deviation of about ±0.15 Hz. The standard deviation of the voltage sensitivity is about ±5 per cent. Variability of both sensitivity and natural period are within the manufacturer's published specifications. Three types of nonlinearities were noted: a 5 per cent difference in parameters determined by positive and negative mass-displacements, possibly due to a nonlinear spring (observed on more than 90 per cent of the 192 components tested); apparent cross-axis errors in wide (1 to 2 Hz) bands near 10 Hz; and spurious resonance peaks at frequencies between 22 and 29 Hz (observed on about 20 per cent of the components). Array equalization of seismograms from the Loma Prieta earthquake aftershock survey indicate that the root mean square misfit between two seismograms recorded by different geophones at the same site can be reduced from ∼10 per cent to ∼5 per cent by application of the calibration results.
On raytracing in an elastic-anelastic medium
Authors: Krebes E. S. , Slawinski M. A.
Published: September 2021

In this article, we investigate seismic wave propagation in a medium consisting of a stack of anelastic layers sandwiched between two half-spaces. The upper half-space is perfectly elastic, and the lower half-space is anelastic. The source is in the upper elastic half-space. To compute a ray going from the source to the receiver (which can be anywhere in the medium), we examine two approaches. The first involves an evaluation of the Sommerfeld wavefield integral by the method of steepest descent, and we refer to the resulting ray as the stationary ray. The second involves assuming that the attenuation vector A1 of the initial ray segment emerging from the source in the elastic half-space is zero (an assumption often made in the literature), and we refer to the resulting ray as the conventional ray. We find that the stationary and conventional rays are, in general, not identical, in that the stationary ray has (a) a complex, rather than real, ray parameter; (b) a smaller travel time; (c) an initial ray segment that corresponds to an inhomogeneous elastic plane body wave (A1 ≠ 0); and (d) a substantially different value for the ray amplitude. The stationary ray actually has the smallest travel time of all possible rays, and hence it is the one that satisfies Fermat's principle of least time. Our results suggest that the stationary ray method is the correct method and that the conventional ray method is generally incorrect. The results might also find application in marine seismology, since water is practically a lossless medium.
Numerical modeling of seismic waves with a 3-D, anisotropic scalar-wave equation
Authors: Dong Zhengxin , McMechan George A.
Published: September 2021

By systematically defining the orientation and amount of velocity anisotropy at every point in a computational grid, and modifying the scalar-wave equation to accommodate directionally dependent velocity coefficients, scalar waves may be numerically synthesized in heterogeneous anisotropic 3-D structure by finite-differencing. The use of an intermediate, local, rotated coordinate system associated with each grid point allows the anisotropy orientation to conform spatially with 3-D structure, stress orientations, or any other correlate of the anisotropy.

Both travel times and amplitudes in anisotropic media may differ significantly from those in the corresponding isotropic media. Under some conditions, the seismic response of an anisotropic flat-layered medium is nearly identical to, and may be confused with, that of a symmetrical isotropic structure. In general, these alternate interpretations can be evaluated by obtaining independent data from different recording configurations.
Seismic hazard sensitivity analysis: A multi-parameter approach
Authors: Rabinowitz Nitzan , Steinberg David M.
Published: September 2021

We propose a novel multi-parameter approach for conducting seismic hazard sensitivity analysis. This approach allows one to assess the importance of each input parameter at a variety of settings of the other input parameters and thus provides a much richer picture than standard analyses, which assess each input parameter only at the default settings of the other parameters. We illustrate our method with a sensitivity analysis of seismic hazard for Jerusalem. In this example, we find several input parameters whose importance depends critically on the settings of other input parameters. This phenomenon, which cannot be detected by a standard sensitivity analysis, is easily diagnosed by our method. The multi-parameter approach can also be used in the context of a probabilistic assessment of seismic hazard that incorporates subjective probability distributions for the input parameters.
High-frequency borehole seismograms recorded in the San Jacinto Fault zone, Southern California. Part 1. Polarizations
Authors: Aster Richard C. , Shearer Peter M.
Published: September 2021

Two borehole seismometer arrays (KNW-BH and PFO-BH) have been established in the Southern California Batholith region of the San Jacinto Fault zone by the U.S. Geological Survey. The sites are within 0.4 km of Anza network surface stations and have three-component seismometers deployed at 300 m depth, at 150 m depth, and at the surface. Downhole horizontal seismometers can be oriented to an accuracy of about 5° using regional and near-regional initial P-wave particle motions.

Shear waves recorded downhole at the KNW-BH indicate that the strong alignment of initial S-wave particle motions previously observed at the (surface) KNW Anza site (KNW-AZ) is not generated in the near-surface weathered layer. The KNW-BH surface instrument, which sits atop a highly weathered zone, displays a significantly different (≈ 20°) initial S-wave polarization direction from that observed downhole and at KNW-AZ, which is bolted to an outcrop. Although downhole initial shear-wave particle motion directions are consistent with a shear-wave splitting hypothesis, observations of orthogonally polarized slow shear waves are generally elusive, even in seismograms recorded at 300 m. A cross-correlation measure of the apparent relative velocities of Sfast and Sslow horizontally polarized S waves suggests shallow shear-wave anisotropy, consistent with the observed initial S-wave particle motion direction, of 2.3 ± 1.7 per cent between 300 and 150 m and 7.5 ± 3.5 per cent between 150 and 0 m.
Observations of Loma Prieta aftershocks from a dense array in Sunnyvale, California
Authors: Frankel Arthur , Hough Susan , Friberg Paul , Busby Robert
Published: September 2021

A small aperture (≈300 m), four-station array was deployed in Sunnyvale, California for 5 days to record aftershocks of the Loma Prieta earthquake of October 1989. The purpose of the array was to study the seismic response of the alluvium-filled Santa Clara Valley and the role of surface waves in the seismic shaking of sedimentary basins. Strong-motion records of the Loma Prieta mainshock indicate that surface waves produced the peak velocities and displacements at some sites in the Santa Clara Valley. We use the recordings from the dense array to determine the apparent velocity and azimuth of propagation for various arrivals in the seismograms of four aftershocks with magnitudes between 3.6 and 4.4. Apparent velocities are generally observed to decrease with increasing time after the S wave in the seismograms. Phases arriving less than about 8 sec after the S wave have apparent velocities comparable to the S wave and appear to be body waves multiply reflected under the receiver site or reflected by crustal interfaces. For times 10 to 30 sec after the direct S wave, we observe long-period (1 to 6 sec) arrivals with apparent velocities decreasing from 2.5 to 0.8 km / sec. We interpret these arrivals to be surface waves and conclude that these surface waves produce the long duration of shaking observed on the aftershock records. Much of the energy in the 40 sec after the S-wave is coming approximately from the direction of the source, although some arrivals have backazimuths as much as 60° different from the backazimuths to the epicenters. Two of the aftershocks show arrivals coming from 30 to 40° more easterly than the epicenters. This energy may have been scattered from outcrops along the southeastern edge of the basin. In contrast, the deepest aftershock studied (d = 17 km) displays later arrivals with backazimuths 30 to 40° more westerly than the epicenter. A distinct arrival for one of the aftershocks propagates from the southwest, possibly scattered from the western edge of the basin. Synthetic seismograms derived from a plane-layered crustal model do not produce the long-period Love waves observed in the waveforms of the ML 4.4 aftershock. These Love waves may be generated by the conversion of incident S waves or Rayleigh waves near the edge of the basin.
Time domain waveform inversion—A frequency domain view: How well we need to match waveforms?
Authors: Der Zoltan A. , Shumway Robert H. , Hirano Michael R.
Published: September 2021

Waveform modeling in the time domain matches the various frequency components of seismic signals unevenly; the agreement is better at low frequencies and becomes progressively worse towards higher frequencies. The net effect of this kind of time-domain modeling is that the resolution in the spatial details of the source is less than optimal since the high-frequency components of the signal with their short wavelengths to resolve finer details do not fit the data. These problems are demonstrated by numerical simulations and by the reanalysis of some aspects of the El Golfo earthquake in using a new seismic imaging technique based on a generalization of an f-k algorithm. This procedure computes a statistic that can be used to derive confidence limits of the parameters sought in the inversion, thus providing a quantitative measure of the uncertainties in the results.
Robótica colaborativa en aplicaciones de asistencia en máquinas de electroerosión
Authors: Abad Román , Muñoz Asier , Flaño Olatz , Ramos Jose Mari , Mancisidor Aitziber , Cabanes Itziar
Published: September 2021

Los robots colaborativos, también denominados cobots, son robots industriales diseñados para dar respuesta a procesos de producción de alta variabilidad y mayor flexibilidad. Estos robots son muy adecuados para tareas de Machine Tending, permitiendo la automatización de los procesos de producción mediante tareas de asistencia a distintos tipos de máquina herramienta. En este trabajo se presenta el diseño de una célula robotizada donde se integra un robot colaborativo para dar respuesta a la necesidad de alimentación de electrodos en diferentes máquinas de electroerosión, sin parar el proceso de mecanizado y colaborando con las tareas a realizar por el usuario. Para la ejecución en simulación se ha implementado dicho escenario en la herramienta RoboDK.
Localizando elementos de interés mediante vehículos operados remotamente para la explotación sostenible de granjas acuícolas
Authors: Gómez-Bravo F. , Garrocho-Cruz A. , Gutiérrez-Estrada J.C. , Pulido-Calvo I. , Castro-Gutiérrez A. , Peregrín-Rubio A. , López-Domínguez S.
Published: September 2021

Este artículo describe una propuesta para modificar la arquitectura de control de un Vehículo Operado Remotamente (ROV) destinado a la toma de datos e inspección de granjas acuícolas. La propuesta se basa en incluir un nuevo módulo de Localización, encargado de posicionar distintos tipos de elementos que se encuentren alrededor del ROV y puedan ser de interés para la explotación de la instalación. El proceso de localización se basa en el uso de un sensor de ultrasonido en conjunción con un sistema de localización del ROV, cuya combinación posibilita el posicionamiento local y global de los elementos de interés. El artículo describe el método de localización desarrollado y presenta resultados experimentales que validan la propuesta.
Aplicaciones de Matlab y Simulink para estaciones robóticas
Authors: Arévalo Fernández Sandra , Herreros López Alberto
Published: September 2021

Se ha diseñado una herramienta de Matlab/Simulink (SimRob) de uso didáctico para diseñar y simular estaciones robóticas. Dicha aplicación se ha realizado usando la herramienta de Matlab Robotic System Toolbox, la herramienta de Simulink SimScape Multi-Body, así como otros paquetes de software libre de Matlab. La mayoría de las aplicaciones de Matlab relacionadas con Robótica no usan el entorno Simulink en el diseño y en las simulaciones de la estación. La aplicación propuesta intenta usar los recursos de Simulink tanto para el diseño de los componentes de la estación como para la simulación de la misma. El control de la simulación, básicamente su cinemática inversa, ha sido desarrollada con las herramientas de Matlab. Con ello se pretende que el alumno disponga de un entorno agradable para diseñar y simular la estación, y unas herramientas en Matlab para su control. Los resultados de la simulación pueden ser exportados a los robot reales usando distintos tipos de comunicación, por ahora, la comunicación OPC.
Prototipo de catéter robótico con sensor háptico basado en visión.
Authors: Bravo Almudena , Rodríguez Castaño Ángel , Vinagre Blas M. , Tejado Inés , Mancha Sánchez Enrique , Rodríguez Paloma , Traver José Emilio
Published: September 2021

El desarrollo de robots como asistentes de procedimientos quirúrgicos mínimamente invasivos está recibiendo un gran interés en los últimos años, fundamentalmente por ofrecer más precisión, flexibilidad y control respecto a las técnicas convencionales. En este artículo se presenta un primer prototipo de catéter autónomo basado en visión, realizando la navegación autónoma por medio del seguimiento de paredes inspirado en animales positivamente tigmotácticos. Además, se llevan a cabo distintos experimentos para verificar la funcionabilidad del prototipo.
Software y computador embarcado basado en cots para el experimento TASEC-Lab
Authors: Pérez Muñoz Ángel Grover , Zamorano Juan , González Bárcena David , de la Puente Juan A.
Published: September 2021

TASEC-Lab es un proyecto desarrollado por estudiantes, con la ayuda de profesores, de los grupos IDR y STRAST de la Universidad Politécnica de Madrid (UPM), que será lanzado a bordo de un globo estratosférico. Su objetivo es caracterizar la transferencia de calor por convección en misiones de este tipo y realizar un estudio del entorno térmico durante las fases de ascenso y flote de la misión. En este artículo se describen los dispositivos y el computador embarcado basados en componentes comerciales (COTS) que han sido empleados en el experimento TASEC-Lab, así como también la arquitectura, metodología y herramientas elegidas para el desarrollo y validación del software de a bordo.
Optimal Configuration Investigation for Photovoltaic Water Pumping System, Case Study: In a Desert Environment at Ghardaia, Algeria
Authors: Benbaha Noureddine , Zidani Fatiha , Bouchakour Abdelhak , Boukebbous Seif Eddine , Nait-Said Mohamed Said , Ammar Hachemi , Bouhoun Salah
Published: September 2021

Since the first installations of solar systems, PV pumping systems have taken a large part in solar energy projects and nowadays they belong to the most significant applications of photovoltaic energy. With the increased use of the PV water pumping systems, sizing and selecting suitable design is essential in order to achieve the most reliable and economic operation for this type of systems. On a real well of 25 m head in desert and semi-arid climate in Sebseb site, Ghardaia, Algeria, a typical PV pumping system for irrigation purpose is installed in order to evaluate its performance under outdoor conditions. Therefore, three PV array configurations are considered to supply a novel version of centrifugal solar pump PS2 C-SJC 12 with a storage tank. The pumped water is used to irrigate 3 hectares of agricultural land. Oversized PV array increases its output power at weak solar irradiance. However, too much oversize will negatively affect the economic reliability. With respect to the wide normal operating range of centrifugal pump, three oversized PV configurations by 4%, 46% and 78% are examined. The experimental results show that PV pumping system can successfully start at low solar radiation 86.21 W/m2 and the optimum performances are obtained with the oversizing of 46%.
The Pandemic Economy
Authors: Credit Kevin , Van Lieshout Emma
Published: September 2021

Since its emergence in 2019, the worldwide spread of the novel coronavirus SARS-CoV-2 (COVID-19) has created a vast economic crisis as government lockdowns place considerable strain on businesses of all kinds – particularly those that rely on face-to-face contact, such as retail restaurants, and personal services. Given the recent emergence of the virus and lags in data collection and publication, the highest-quality fine-grained spatial datasets on economic behavior will not reflect virus-related impacts for at least a year. At the same time, in order to make evidence-based decisions on policies regarding continuing lockdown and/or re-opening policies, local governments and researchers need to understand neighborhood-level economic effects much sooner than that. This paper makes use of the point-level Chicago Business License dataset, which is updated on a weekly basis, to examine the impact of the COVID-19 pandemic on new business activity in the City of Chicago. The results indicate that on average, from March to September 2020, total monthly new business starts have declined by 33.4% compared to the monthly average of new starts in the City from January 2016 to December 2019. Food service and retail businesses have been hardest hit during this period, while chains of all types have seen larger average declines in new startup activity than independent businesses. These patterns demonstrate interesting intra-urban spatial heterogeneity; ZIP codes with the largest pandemic-related declines in new business activity tend to be have larger rates average rates of new business creation to begin with and also have less dense, diverse, and walkable built environments (defined in more detail below), while, interestingly, observed COVID-19 case rates do not appear to have an individually-significant impact on new business deficits.
A Historical View of Library Instructional Podcasts Demonstrating They Were Beneficial to Students and Staff at a New Zealand College of Learning
Authors: Kathmann Mackenzie
Published: September 2021

A Review of:
Jowitt, A. (2008). Perceptions and usage of library instructional podcasts by staff and students at New Zealand’s Universal College of Learning (UCOL). Reference Services Review, 36(3), 312–336. https://doi.org/10.1108/00907320810895396
Abstract
Objective – To examine usage of a specific set of library instructional podcasts and the potential of the format for effective library instruction.
Design – Concurrent mixed methods survey.
Setting – Multiple campuses at a polytechnic college in New Zealand.
Subjects – A total of 86 self-selected, non-random students and staff.
Methods – Web-based survey, piloted before a broader launch, with open and closed questions in one survey instrument (SurveyPro) regarding six sample podcasts accessible via the college’s library website. The researcher used closed questions to gather quantitative data with Likert and verbal frequency scales and used concurrent triangulation to ensure balance with qualitative open-ended question responses for proper later interpretation.
Main Results – Of the 86 participants in the study, 71.1% responded that the five library podcasts were “very good.” The study determined that the most useful podcast was called “My account” and helped students and staff activate and use their library accounts. Overall, students enjoyed the five library podcasts slightly more than staff. The orientation walking tour was the least popular podcast. The researchers hypothesized that this was because the podcast did not fit the users’ preferred medium, which was computer based. Even listeners who owned a portable media device preferred using a media player on their computer to access the podcasts. The participants preferred to listen to the podcasts during the day. The participants found that the 24/7 availability and the ability to listen to the material repeatedly were particularly helpful features.
Conclusion – Based on the research results, students and staff found library instructional podcasting advantageous because of its ease of access and constant availability. Some participants mentioned ways to improve the quality of the podcasts, but they found them to be an effective new medium overall. Additional research is needed to evaluate podcasts as an instructional medium.
REPRODUCTIVE PERFORMANCE OF BROWN SWISS AND MESTIZO BOVINE IN HUMID TROPIC
Authors:   Universidad Nacional Amazónica de Madre de Dios. Tambopata, Madre de Dios, Peru, Troncoso Ramon , Medina C , Reategui Juan
Published: September 2021

The ability of ruminants to regulate body temperature depends on the genotype. Dairy breeds are generally more sensitive to heat stress than beef breeds. Higher-producing animals are more susceptible to heat stress because they generate more metabolic heat. The objective of evaluating reproductive performance as a response of adaptability to the management and climatic conditions of the Humid Tropics. 78 animals were used (40 Brown Swiss, from Puno and 38 Mestizas from local origin) raised in humid tropic conditions. Parametric statistics are presented as analysis of measures of central tendency and dispersion, non-parametric statistics by frequency analysis, the χ2 test of independence was used to detect differences, α = 0.05. The categorized and continuous dependent variables were evaluated with Student's t test using SPSS Software v.23. The mean age at first estrus in Brown Swiss was 12.43 months, in mestizo cattle 18.68 months (P <0.05). Average age of first calving in Brown Swiss of 25.25 months versus mestizo cattle 28.34 months (P <0.05). Interval from calving to the first service in Brown Swiss was 99.29 days. Open days observed in Brown Swiss was 107.29 days. The pregnancy rate at the first service in Brown Swiss was 70.0% pregnancy at the first service and 30.0% at the second service, for the mestizo genotype it was 68.4% at the first service, 28.9 at the second and 2.6 at the third service (P> 0.05; X2 = 0.50; p = 0.47). It is concluded that bovine animals of the Brown Swiss genotype have a good reproductive performance in the Humid Tropic climate compared to the Mestizo genotype
Ackermann Principle and its Implementation in Modern Cars
Authors: Ioffe M.L.
Published: September 2021

The Ackermann principle was developed when it became possible to separately control the four wheels of a moving object in the process of turning. In this case, two tasks arose. The first task was to control the wheels to ensure their pure rolling when the object is turned. The solution of this problem was in the Ackermann principle. The second task was to implement this principle in a specific mechanism. The paper analyzes the mechanisms common in modern cars in order to assess their compliance with the Ackermann principle. The method of analysis was in generating and modeling a finite-difference equation describing the process of transferring the movement of the steering wheel to the movement required to turn the wheels.
¡Sálvese quien pueda! Propuestas sobre la aplicación de la excepción de empresa en crisis
Authors: Bocanegra Abarca Gianfranco , Calderón Rojas Ximena
Published: September 2021

El COVID-19 ha generado, indudablemente, una crisis empresarial que no será sencilla de resolver. En este contexto, la figura de la excepción de la empresa en crisis cobra especial relevancia, al haber sido introducida de manera expresa por unos meses en la legislación peruana con ocasión de la pandemia a través del Decreto Legislativo 1510, con la finalidad de que la agencia de competencia tome este aspecto en consideración en sus decisiones en materia de control de concentraciones. Si bien, posteriormente a través de la Ley 31112, Ley que establece el control previo de operaciones de concentración empresarial, ya no se menciona la excepción de la empresa en crisis, esta ley deja abierta la posibilidad de su aplicación. En el presente texto, los autores analizan la figura de la excepción de la empresa en crisis o failing firm defense, con el fin de entender su importancia en el contexto crítico de la pandemia. Asimismo, proponen lineamientos y modificaciones para fortalecer la regulación de la Ley 31112.
La coherencia de la disciplina del dumping con la disciplina de la libre competencia en el Perú: el caso de dumping de la República Popular de China
Authors: Cannock Geoffrey , Ezcurra Rodrigo
Published: September 2021

En el Perú, la autoridad de competencia, el Indecopi, mantiene al mismo tiempo la función de velar por la libre competencia y la de proteger a los mercados de las supuestas distorsiones de las prácticas del dumping. Ello es incoherente ya que ambas disciplinas se inspiran en principios opuestos: una favorece el libre intercambio mientras que la otra tiende al proteccionismo. En el presente artículo, los autores abordan las políticas de dumping del Indecopi y cómo estas pueden colisionar con el respeto a la libre competencia. Para ello, analizan la base legal del Acuerdo Antidumping de la OMC en el Perú, exponen el sustento teórico y los efectos de la práctica del dumping y, finalmente, desarrollan un análisis crítico de las medidas antidumping que el Indecopi ha impuesto sobre el calzado chino. Este marco permite a los autores elaborar una serie de recomendaciones para mejorar el funcionamiento del Indecopi en esta materia.