Unknown Ground Research Articles

A Miocene breeding ground of an extinct baleen whale (Cetacea: Mysticeti).

Locating breeding sites is definitely a key to understanding the ecological requirements and maintaining the sustainability of populations/species. Here I re-examined published specimens of an extinct baleen whale, Parietobalaena yamaokai, from the lower part of Itahashi Formation (16.1–15.6 Ma, Middle Miocene) in Shobara, Hiroshima, Japan. A critical and previously unnoticed feature, the open suture between the supraoccipital and exoccipital, in one specimen indicates the preservation of a very young individual–under six months old and even close to a new-born calf. Given the occurrence of a new-born whale and relatively abundant assemblage of Parietobalaena yamaokai, I propose a previously hidden and unknown breeding ground for the extinct baleen whale, P. yamaokai, in the Middle Miocene of Shobara (16.1–15.6 Ma), Hiroshima. Discovery of paleo-breeding sites of extinct populations/species should further help us to understand biological extinctions from a long-term perspective as conservation paleobiology aims to offer new insights into policy making for conserving endangered populations/species.

High Thermoelectric Performance in n-Doped Silicon-Based Chalcogenide Si2Te3

Achieving large thermoelectric figure of merit in a low-cost material, having an appreciable degree of compatibility with the modern technology is required to convert waste heat into electrical energy efficiently. Using first-principles density functional theory and semiclassical Boltzmann transport theory, we report high thermoelectric performance of a silicon-based chalcogenide Si2Te3. Previously unknown ground state structure of Si2Te3 was obtained by finding out the 8 most energetically favorable sites for Si in a unit cell of 12 Te and 8 Si atoms. Out of total C(28,8) combinations of structures, the search was narrowed down to 15 by using Wyckoff positions of space group P31c. The minimum energy configuration having layered structure exhibits combination of desirable electronic and transport properties for an efficient thermoelectric material, including confinement of heavy and light bands near the band edges, large number of charge carrier pockets and low conductivity effective mass for n-type carr...

Adaptively Controlled Dynamical Behavior of Sensory Systems Based on Mechanoreceptors

This paper presents results on adaptive control strategies for a sensory system to identify (unknown) ground excitations which force the sensor and its seismic masses, so that acting forces can be measured and identified. The sensor system is modeled as a spring-mass-damper system within a rigid frame with two degrees-of-freedom. The seismic masses are under the load of internal control forces, which shall ensure stabilization of the mass point rest positions despite the continuing ground excitations. Using these (measured) resulting regulating forces, we are able to identify the excitation force. The control strategies are designed referring to the natural behavior of mechanoreceptors from biology. These are able to adapt their sensitivity to the environment, so that they filter the important information out of the flood of information. Mimicking this behavior, adaptive control strategies are used with time-varying controller gains. In this way, we are able to design controllers which are still sensitive while a constant stimuli affects. So new incoming information can be identified with a high quality. Further on, the sensor has to be universal and shall consume less energy as possible. Therefore, control strategies from literature are analyzed and modified, so that the most effective ones are used for the sensor system in this paper. Finally, the best working control strategies are tested for both their long-term behavior to an excitation which simulates different situations and for their response to different system parameters, chosen randomly.

Layover Analysis in Synthetic Aperture Imagery

Layover is an artifact observed in synthetic aperture radar (SAR) images. This artifact manifests as geometric distortions or positioning errors due to unknown or inaccurate ground topography information. Layover artifact results in erroneous distance between reconstructed scatterers, particularly in elevated regions. We develop a quantitative analysis of positioning errors due to incorrect height information in backprojection based (BP) SAR image formation. Our analysis is based on microlocal techniques and provides an explicit algebraic relationship between the two-dimensional positioning error and height error. Our analysis is applicable to arbitrary imaging geometries including bistatic configuration, arbitrary antenna trajectories, wide apertures, and large scenes. While we focus primarily on BP based image formation, the results are also applicable to range-Doppler type image formation methods. Our results can be used to interpret and identify layover regions in SAR images and extract valuable information from layover artifacts.

Structural control and health monitoring of building structures with unknown ground excitations: Experimental investigation

When health monitoring system and vibration control system both are required for a building structure, it will be beneficial and cost-effective to integrate these two systems together for creating a smart building structure. Recently, on the basis of extended Kalman filter (EKF), a time-domain integrated approach was proposed for the identification of structural parameters of the controlled buildings with unknown ground excitations. The identified physical parameters and structural state vectors were then utilized to determine the control force for vibration suppression. In this paper, the possibility of establishing such a smart building structure with the function of simultaneous damage detection and vibration suppression was explored experimentally. A five-story shear building structure equipped with three magneto-rheological (MR) dampers was built. Four additional columns were added to the building model, and several damage scenarios were then simulated by symmetrically cutting off these columns in certain stories. Two sets of earthquakes, i.e. Kobe earthquake and Northridge earthquake, were considered as seismic input and assumed to be unknown during the tests. The structural parameters and the unknown ground excitations were identified during the tests by using the proposed identification method with the measured control forces. Based on the identified structural parameters and system states, a switching control law was employed to adjust the current applied to the MR dampers for the purpose of vibration attenuation. The experimental results show that the presented approach is capable of satisfactorily identifying structural damages and unknown excitations on one hand and significantly mitigating the structural vibration on the other hand.

Heterogeneous Model Integration for Multi-Source Urban Infrastructure Data

Data-driven modeling usually suffers from data sparsity, especially for large-scale modeling for urban phenomena based on single-source urban-infrastructure data under fine-grained spatial-temporal contexts. To address this challenge, we motivate, design, and implement UrbanCPS, a cyber-physical system with heterogeneous model integration, based on extremely-large multi-source infrastructures in the Chinese city Shenzhen, involving 42,000 vehicles, 10 million residents, and 16 million smartcards. Based on temporal, spatial, and contextual contexts, we formulate an optimization problem about how to optimally integrate models based on highly diverse datasets under three practical issues, that is, heterogeneity of models, input data sparsity, or unknown ground truth. We further propose a real-world application called Speedometer, inferring real-time traffic speeds in urban areas. The evaluation results show that, compared to a state-of-the-art system, Speedometer increases the inference accuracy by 29% on average.

Output-only subspace identification of structural properties and unknown ground excitation for shear-beam buildings

A novel output-only subspace identification method is proposed to estimate the structural parameters of a shear-beam building under unknown ground excitation. The unique feature of the method is that both the structural parameters and the ground acceleration can be identified using only the absolute acceleration response, and no displacement and velocity responses are required. The method uses two subspace identification techniques sequentially and iteratively. The first technique extracts modal parameters of the building (natural frequencies, damping ratios, and mode shapes) using the absolute acceleration response and assumed or identified ground acceleration. These modal parameters further lead to the estimation of the building’s structural parameters when the mass properties of the building are known. The second technique then estimates the ground acceleration using the absolute acceleration and the obtained structural parameters from the first technique. The two techniques are performed iteratively until the estimated structural parameters converge. A numerical example and a laboratory test are used to illustrate the proposed identification method. Results show that the estimation of structural parameters is fairly robust to the presence of measurement noise while the unknown ground acceleration is not in high frequency range. Factors influencing the performance of the technique are also studied and discussed.

Estimation of source location and ground impedance using a hybrid multiple signal classification and Levenberg–Marquardt approach

A microphone array signal processing method for locating a stationary point source over a locally reactive ground and for estimating ground impedance is examined in detail in the present study. A non-linear least square approach using the Levenberg–Marquardt method is proposed to overcome the problem of unknown ground impedance. The multiple signal classification method (MUSIC) is used to give the initial estimation of the source location, while the technique of forward backward spatial smoothing is adopted as a pre-processer of the source localization to minimize the effects of source coherence. The accuracy and robustness of the proposed signal processing method are examined. Results show that source localization in the horizontal direction by MUSIC is satisfactory. However, source coherence reduces drastically the accuracy in estimating the source height. The further application of Levenberg–Marquardt method with the results from MUSIC as the initial inputs improves significantly the accuracy of source height estimation. The present proposed method provides effective and robust estimation of the ground surface impedance.

Dating Strong Prehistoric Earthquakes and Estimating Their Recurrence Interval Applying Radiocarbon Analysis and Dendroseismological Approach – Case Study from SE Altai (Russia)

Earthquakes are some of the most disastrous geohazards. The recurrence interval of strong earthquakes is a crucial characteristic for seismic hazard risk assessment. In this context absolute age determination of ancient earthquakes is one of the key problems. This paper presents the results of our geomorphological, paleoseismogeological, and geochronological investigations in seismically active southeastern part of Russian Altai. To specify the Holocene recurrence interval of strong earthquakes in the SE Altai we used radiocarbon and tree ring analysis. Twenty-five new radiocarbon ages were obtained for previously unknown effects of prehistoric earthquakes located near the southern fault boundary of the Chagan-Uzun massif and were reactivated during the 2003 Chuya earthquake. Results obtained argue for high regional seismicity in the second half of the Holocene and indicate the Chagan-Uzun massif to be one of the major seismogenic neotectonic structure within the SE Altai. Strong earthquakes occurred here about 600-700, 1,300-1,500, 2,400-2,700, and 3,400-3,700 and 3,800-4,200 cal. BP. Together with the previously published radiocarbon dates these data clarify the chronology of seismic events within the SE Altai. The specified recurrence interval of strong earthquakes for the SE Altai is about 400 years during the last 4,000 years. Numerous evidences of several seismic excitations were found in sediments from the largest landslide triggered by the 2003 Chuya earthquake. This argues for repeated activization of the same earthquake source zones in the SE Altai during the Holocene. Seismic activization of the fault boundaries of the Chagan-Uzun massif in the late Pleistocene-Holocene, as well as in 2003, was accompanied by its rotation counter clock-wise with the prevailing displacement along dextral strike-slip faults of NW direction. This is supported by results of our geomorphological investigations and previously unknown ground effects of the 2003 Chuya earthquake in the central part of the Chagan-Uzun massif.

Adaptive rendering with linear predictions

We propose a new adaptive rendering algorithm that enhances the performance of Monte Carlo ray tracing by reducing the noise, i.e., variance, while preserving a variety of high-frequency edges in rendered images through a novel prediction based reconstruction. To achieve our goal, we iteratively build multiple, but sparse linear models. Each linear model has its prediction window, where the linear model predicts the unknown ground truth image that can be generated with an infinite number of samples. Our method recursively estimates prediction errors introduced by linear predictions performed with different prediction windows, and selects an optimal prediction window minimizing the error for each linear model. Since each linear model predicts multiple pixels within its optimal prediction interval, we can construct our linear models only at a sparse set of pixels in the image screen. Predicting multiple pixels with a single linear model poses technical challenges, related to deriving error analysis for regions rather than pixels, and has not been addressed in the field. We address these technical challenges, and our method with robust error analysis leads to a drastically reduced reconstruction time even with higher rendering quality, compared to state-of-the-art adaptive methods. We have demonstrated that our method outperforms previous methods numerically and visually with high performance ray tracing kernels such as OptiX and Embree.

Determination of compounding formulation of cured rubber by reverse engineering

The present work deals with reverse engineering on four rubber formulations. Information about the material composition of the compounding formulations was obtained by using techniques such as acetone extract, thermogravimetric analysis, energy dispersive X‐ray fluorescence studies, and Fourier transform infrared (FTIR) spectroscopy in attenuated total reflection mode. The reverse engineered formulations were compared on a qualitative and quantitative basis with the initial formulations. The aim was to ascertain the validity of the methodology, which may be used as reverse engineering of rubber compounds to quantitatively analyze unknown ground tire rubber in future. The state of the art was based on a fractional mass transfer from acetone extract to the rubbers detected in TGA. Through this new approach, the formulations calculated were very consistent with the formulations employed, thus establishing the validity of the methodology used. POLYM. ENG. SCI., 55:1450–1458, 2015. © 2015 Society of Plastics Engineers

Learning from automatically labeled data: case study on click fraud prediction

In the era of big data, both class labels and covariates may result from proprietary algorithms or ground models. The predictions of these ground models, however, are not the same as the unknown ground truth. Thus, the automatically generated class labels are inherently uncertain, making subsequent supervised learning from such data a challenging task. Fine-tuning a new classifier could mean that, at the extreme, this new classifier will try to replicate the decision heuristics of the ground model. However, few new insights can be expected from a model that tries to merely emulate another one. Here, we study this problem in the context of click fraud prediction from highly skewed data that were automatically labeled by a proprietary detection algorithm. We propose a new approach to generate click profiles for publishers of online advertisements. In a blinded test, our ensemble of random forests achieved an average precision of only 36.2 %, meaning that our predictions do not agree very well with those of the ground model. We tried to elucidate this discrepancy and made several interesting observations. Our results suggest that supervised learning from automatically labeled data should be complemented by an interpretation of conflicting predictions between the new classifier and the ground model. If the ground truth is not known, then elucidating such disagreements might be more relevant than improving the performance of the new classifier.

Magnetic phase diagram of pseudo-ternary solid solution [formula omitted

A systematic study of the solid solution URu1−xPdxGeby means of X-ray diffraction, dc-magnetization, specific heat and electrical resistivity measurements is presented. The investigated alloys (0.0≤x≤0.9) crystallize in the orthorhombic TiNiSi-type structure with space group Pnma. The variation of the unit cell volume with Pd content x follows approximately Vegard׳s law, through the lattice parameters a, b and c exhibit a little anomaly around x=0.35, 0.7 and 0.8, respectively. It is found that the magnetic ground state of URu1−xPdxGestrongly depends on Pd content. The compositions with x≤0.32 are nonmagnetic down to 0.4K, while these in the concentration range 0.35≤x≤0.8 order antiferromagnetically. The Néel temperature TN is found to follow a relation TN∝(x−0.32)2/3 for the alloys x<0.45 and to attain a maximum value of 32K at x=0.8. The composition x=0.9 alike UPdGe manifests a complex magnetic order, probably undergoes two successive magnetic phase transitions: ferromagnetic-like at TC=33K and unknown ground state characterized by an irreversible magnetization below TIR. The observed development of magnetism has been discussed in terms of changes in the degree of 5f electron localization as well as due to the competition between the Kondo and Ruderman–Kittel–Kausuya–Yosida interactions. Remarkably, in the compound x=0.32 located at the nonmagnetic-magnetic border, we found a non-Fermi liquid behaviour reflected by the power-law temperature dependencies of magnetic susceptibility χ(T)∝T−0.48, specific heat Cp(T)∝−T and electrical resistivity ρ(T)∝T3/2. We compared the results with theoretical predictions for systems with spin fluctuations nearby antiferromagnetic quantum critical point.

A Control Strategy for Slip Regulation Coordinated with Driver Intention

Aiming at improvement of the dynamic performance of in-wheel-drive electric vehicles, an approach to coordinate wheel slip ratio tracking with fulfilling driver’s desired torque is presented. First, an anti-windup PI controller for slip ratio tracking regardless the unknown ground adhesion, is proposed, followed by its stability analysis base on Lyapunov theory. Second, a coordinating logic is designed to guarantee that the slip ratio tracking control engages only when driver’s desired tracking or braking motor torque may cause the wheel to spin or lock. The performance of the control strategy is supported by simulation and experimental results.

Without a Face: A Silver Plaque from the Eastern Slopes of the Urals

This article provides a description and preliminary interpretation of a unique discovery from a previously unknown burial ground in the Konda River basin (Sovetsky Region of the Khanty-Mansi Autonomous District–Yugra); the discovery represents a silver plaque from the 9th–10th century. The plaque has a fragment missing that bears the representation of the head (and presumably the face) of a male figure. This suggests that the missing fragment's exclusion from burial was intentional and that the missing fragment was subsequently used to produce a figure of the deceased as a receptacle for his soul. An appendix to this article contains the results of traceological analysis for the plaque's fragmentation during burial ritual.

Identification of Tall Shear Buildings under Unknown Seismic Excitation with Limited Output Measurements

Due to the fact that some structural external excitations such as earthquakes and wind forces can not be accurately measured under actual operating conditions, it is necessary to investigate algorithms for structural identification under unknown earthquakes. In this paper, an algorithm based on the extended Kalman estimator approach is proposed for the identification of structural parameters and unknown excitation of tall shear-type buildings with only partial measurements of structural absolute acceleration responses. The equation of motion of a tall shear building under ground motion is established in the absolute co-ordinate system, in which the ground-motion input is applied to the 1st floor of the building as an unknown excitation. Based on substructure approach, the tall building is decomposed into substructures. For each substructure above the 1st floor, substructural relative responses and parameters are identified by extended Kalman estimator. For the substructure containing the 1st floor, it is proposed that substructural extended state vector is firstly identified by the extended Kalman estimator and the unknown excitation is subsequently estimated by least-squares estimation. Then, the 1st story stiffness is estimated based on structural eigenvalue equation and the expansion of the determinate of the structural eigen-matrix. The unknown ground motion is identified by the Newmark-β method. A numerical simulation example demonstrates the efficiency of the proposed algorithm.

From burials to population identity: archaeological appraisal of the status of a Lesser Antilles colonial cemetery (Baillif, Guadeloupe)

Settlements and cemeteries associated with a European colonial presence provide rich opportunities to gain insights into the character and composition of those populations, even in the absence of written records. The study reported here has the added fascination of a detective story, seeking to match an unknown burial ground to a series of known but long lost cemeteries. The systematic analysis of the graves and their occupants is carried out within a comparative framework which highlights the variable composition and distinguishing features of the different types of graveyard that are encountered within a colonial context. The authors conclude that the Baillif cemetery was a nineteenth-century military graveyard, and that many of the young men who were buried here were new recruits who fell victim to endemic diseases such as dysentery, yellow fever and malaria.

Integration of decentralized structural control and the identification of unknown inputs for tall shear building models under unknown earthquake excitation

Since some excitations such as earthquakes or wind forces cannot be accurately measured, it is necessary to explore algorithms which can integrate structural control and the identification of unknown excitations. In this paper, an algorithm is proposed for the decentralized structural control of tall shear-type buildings under unknown earthquake-induced ground motion. The equations of motion of a tall controlled shear building subject to unknown ground motion are established in the absolute co-ordinate system, in which the ground motion input is applied to the 1st floor of the building and treated as an unknown external excitation. A decentralized control algorithm based on the instantaneous optimal control scheme is developed with limited measurements of structural absolute acceleration responses. The inter-connection effect between adjacent substructures is treated as ‘additional unknown disturbances’ at substructural interfaces to each substructure. Instantaneous optimal control forces are obtained by sequentially utilizing a Kalman estimator for the substructural state vector and least square estimation of the ‘additional unknown disturbances’. Then, unknown ground motion is subsequently estimated by the Newmark-β method. To validate the performances of the proposed algorithm, two numerical examples of decentralized control of tall building models under unknown earthquake excitations are studied and the simulation results are compared with those by the conventional centralized control under measured earthquake excitation.

Preliminary hazard assessment and site characterization of Meşelik campus area, Eskişehir-Turkey

Abstract. Limited knowledge of ground conditions, such as geotechnical parameters, is one of the main causes of foundation failure. Unknown ground conditions can also cause additional burden costs. Due to lack of geotechnical parameters in foundation soil, some problems can be observed during and after the construction. In this study, a comprehensive field study was conducted to make a preliminary hazard assessment on the Meşelik campus area, Eskişehir, Turkey. In this context, the experimental studies were performed in two stages. In the first stage, boreholes were drilled in the field; a standard penetration test (SPT) was performed and disturbed/undisturbed samples were collected from certain levels. In the second stage, laboratory tests were performed in order to identify and classify the samples. Unconfined compression strength and triaxial compression tests were conducted on undisturbed samples for determining the engineering characteristics. XRD (X-ray diffraction) tests were performed and the swelling potential of the samples were evaluated. The liquefaction potential of the area was also assessed on a SPT-based method. Thus, the geotechnical parameters and the liquefaction potential of the sub-surface in the study area were thoroughly analyzed and presented to be used for further studies.

Mixed Marker-Based/Marker-Less Visual Odometry System for Mobile Robots

Abstract When moving in generic indoor environments, robotic platforms generally rely solely on information provided by onboard sensors to determine their position and orientation. However, the lack of absolute references often leads to the introduction of severe drifts in estimates computed, making autonomous operations really hard to accomplish. This paper proposes a solution to alleviate the impact of the above issues by combining two vision-based pose estimation techniques working on relative and absolute coordinate systems, respectively. In particular, the unknown ground features in the images that are captured by the vertical camera of a mobile platform are processed by a vision-based odometry algorithm, which is capable of estimating the relative frame-to-frame movements. Then, errors accumulated in the above step are corrected using artificial markers displaced at known positions in the environment. The markers are framed from time to time, which allows the robot to maintain the drifts bounded by additionally providing it with the navigation commands needed for autonomous flight. Accuracy and robustness of the designed technique are demonstrated using an off-the-shelf quadrotor via extensive experimental tests.