A consistent combination of GNSS and SLR with minimum constraints

2015 ◽  
Vol 89 (12) ◽  
pp. 1165-1180 ◽  
Author(s):  
Susanne Glaser ◽  
Mathias Fritsche ◽  
Krzysztof Sośnica ◽  
Carlos Javier Rodríguez-Solano ◽  
Kan Wang ◽  
...  
Keyword(s):  
Minimum Constraints

scholarly journals Extraction of the deterministic ingredient of a dynamic geodetic control network

2012 ◽  
Vol 2 (1) ◽  
pp. 68-75 ◽  
Author(s):  
L. Shahar ◽  
G. Even-Tzur
Keyword(s):  
Kinematic Model ◽  
Simultaneous Estimation ◽  
Physical Parameters ◽  
Control Network ◽  
Deformation Parameters ◽  
Free Network ◽  
Geodetic Control ◽  
Definition Of ◽  
Minimum Constraints ◽  
Entire Network

Extraction of the deterministic ingredient of a dynamic geodetic control networkA minimum constraints solution, which resolves the datum defect of a control network, is an arbitrary solution that may result in a systematic error in the estimation of the deformation parameters. This error is not derived from measurements and is usually inconsistent with the geophysical reality. A free network is affected only by errors of measurement and, therefore, a free network is an accepted way of coping with this problem. Study of deformations, which is based on the use of geodetic measurements, is usually performed today by defining a kinematic model. Such a model, when used to describe a complex geophysical environment, can lead to the partial estimation of the deterministic dynamics, which characterize the entire network. These dynamics are themselves expressed in measurements, as the adjustment systems' residuals. The current paper presents an extension of the definition of the parameters that are revalued. This extension enables the cleaning of measurements by means of the extraction of datum elements that have been defined by geodetic measurement. This cleaning minimizes the effects of these elements on the revaluated deformation. The proposed algorithm may be applied to achieve the simultaneous estimation of the physical parameters that define the geophysical activity in the network.

Effective Storm-Relative Helicity and Bulk Shear in Supercell Thunderstorm Environments

2007 ◽  
Vol 22 (1) ◽  
pp. 102-115 ◽  
Author(s):  
Richard L. Thompson ◽  
Corey M. Mead ◽  
Roger Edwards
Keyword(s):  
Lower Bounds ◽  
Broad Spectrum ◽  
Model Analysis ◽  
Vertical Shear ◽  
Upper And Lower Bounds ◽  
Wide Range ◽  
Equilibrium Level ◽  
Supercell Thunderstorm ◽  
Convective Inhibition ◽  
Minimum Constraints

Abstract A sample of 1185 Rapid Update Cycle (RUC) model analysis (0 h) proximity soundings, within 40 km and 30 min of radar-identified discrete storms, was categorized by several storm types: significantly tornadic supercells (F2 or greater damage), weakly tornadic supercells (F0–F1 damage), nontornadic supercells, elevated right-moving supercells, storms with marginal supercell characteristics, and nonsupercells. These proximity soundings served as the basis for calculations of storm-relative helicity and bulk shear intended to apply across a broad spectrum of thunderstorm types. An effective storm inflow layer was defined in terms of minimum constraints on lifted parcel CAPE and convective inhibition (CIN). Sixteen CAPE and CIN constraint combinations were examined, and the smallest CAPE (25 and 100 J kg−1) and largest CIN (−250 J kg−1) constraints provided the greatest probability of detecting an effective inflow layer within an 835-supercell subset of the proximity soundings. Effective storm-relative helicity (ESRH) calculations were based on the upper and lower bounds of the effective inflow layer. By confining the SRH calculation to the effective inflow layer, ESRH values can be compared consistently across a wide range of storm environments, including storms rooted above the ground. Similarly, the effective bulk shear (EBS) was defined in terms of the vertical shear through a percentage of the “storm depth,” as defined by the vertical distance from the effective inflow base to the equilibrium level associated with the most unstable parcel (maximum θe value) in the lowest 300 hPa. ESRH and EBS discriminate strongly between various storm types, and between supercells and nonsupercells, respectively.

Efficient Mining of Partial Periodic Patterns with Individual Event Support Thresholds Using Minimum Constraints

2014 ◽  
Vol 22 (06) ◽  
pp. 793-814
Author(s):  
Kung-Jiuan Yang ◽  
Tzung-Pei Hong ◽  
Guo-Cheng Lan ◽  
Yuh-Min Chen
Keyword(s):  
Real World ◽  
Execution Time ◽  
Real Life ◽  
Individual Event ◽  
Periodic Patterns ◽  
Minimum Support ◽  
Real World Applications ◽  
Support Threshold ◽  
Multiple Minimum Supports ◽  
Minimum Constraints

Partial periodic patterns are commonly seen in real-life applications and provide useful prediction with uncertainty. Most previous approaches have set a single minimum support threshold for all events to assume they have similar frequencies which is not practical for real-world applications. Instead of setting a single minimum support threshold for all events, Chen et al. proposed an FP-tree-like algorithm to allow multiple minimum supports for reflecting the natures of the events. However, such a tree-based algorithm encountered an efficiency problem while period length is long or event sequential orders in period segments are varied. Under the circumstance, many tree branches are created and much execution time is spent to find partial periodic patterns. In this paper, we thus propose a projection-based algorithm which examines only prefix subsequences and projects only corresponding postfix subsequences with multiple minimum supports to quickly find the partial periodic patterns in a recursive process. Experiments on both synthetic and real-life datasets show that the proposed algorithm is more efficient than the previous one.

Sustainable Production Enhancement of Valuable Products Via Operational Rectification

2021 ◽  
Author(s):  
Margono Agung ◽  
Wawan Heryadi ◽  
SanthoshKumar Selladurai ◽  
Ramesh Ventkataraman ◽  
Ahmed Al Qubati ◽  
...  
Keyword(s):  
Value Chain ◽  
Growth Strategy ◽  
Chain Process ◽  
Quality Improvements ◽  
Market Competitiveness ◽  
Middle Stream ◽  
Trial Basis ◽  
Added Benefit ◽  
Minimum Constraints ◽  
Performance Trial

Abstract ADNOC LNG lies in the middle stream of the value chain, receiving and processing LP and HP gases from ADNOC Offshore. Supporting ADNOC Upstream's current oil production and future growth strategy while reducing its associated emissions of the process by delivering the associated gases to ADNOC LNG battery limit ADNOC LNG processes associated and non-associated gases to produce LNG (Liquefied Natural Gas), Propane, Butane, Paraffinic Naphtha (P. Naphtha) and Sulfur. LNG constitutes Methane, Ethane and a little Propane and butane, with minimum constraints on GHV and density. In order to deal with market competitiveness in the context of a potentially prolonged low-price environment, ADNOC LNG has embarked on various initiatives to maximize its production by driving agility and efficiency throughout the value chain process. Delivering upon efficiency improvements, one of the contributing studies included optimizing the propane content i.e. reducing the C3 content, in LNG Propane content in LNG has been varied, within operational limits, to maximize production of propane, which is more valuable/profitable when compared to LNG, whilst maintaining minimum LNG specification. In addition, slighting higher feed gas has been processed, to maintain LNG production rate. This has been achieved without hampering the plant stability. The extensive review and analysis of the rectification units has been conducted as well as optimization in terms of temperature profiles and reflux flow rates was able to generate overall better product purification, thereby increasing production of desired and more valuable products. This study has driven the investigation of additional benefits in production enhancement and quality improvements as the market value of Propane is relatively higher than that of LNG and thus yielding greater benefits. The overall performance trial basis deduced a total added benefit equivalent to 9 MMUSD/year YTD for train 3.

Sources of Solar Wind at Solar Minimum: Constraints from Composition Data

2012 ◽  
pp. 41-55
Author(s):  
Thomas H. Zurbuchen ◽  
Rudolf von Steiger ◽  
Jacob Gruesbeck ◽  
Enrico Landi ◽  
Susan T. Lepri ◽  
...  
Keyword(s):  
Solar Wind ◽  
Solar Minimum ◽  
Composition Data ◽  
Minimum Constraints

scholarly journals Verification of the Polish Geodetic Reference Frame by Means of a New Solution Based on Permanent GNSS Data from the Years 2011-2014

2016 ◽  
Vol 102 (1) ◽  
pp. 52-66 ◽  
Author(s):  
T. Liwosz ◽  
M. Ryczywolski
Keyword(s):  
Reference Frame ◽  
Primary Network ◽  
Position Time Series ◽  
Gnss Network ◽  
Gnss Data ◽  
Geodetic Reference Frame ◽  
Minimum Constraints ◽  
Data Length ◽  
Good Agreement

Abstract The new solution for the Polish geodetic primary GNSS network was created to verify the currently used reference frame (PL-ETRF2000). The new solution is based on more GNSS data (more daily observation sessions included, a longer data timespan, GLONASS observations added) which were processed in a newer reference frame (IGb08) according to up-to-date methodology and using the latest version of Bernese GNSS Software. The new long-term solution (spanning 3.7 years) was aligned to the IGb08 reference frame using a minimum constraints approach. We categorized Polish reference stations into two categories according to their data length. We obtained good agreement of the new solution with the PL-ETRF2000: for most stations position differences did not exceed 5 mm in horizontal, and 10 mm in vertical components. However, for 30 stations we observed discontinuities in position time series, mostly due to GNSS equipment changes, which occured after the introduction of PL-ETRF2000. Position changes due to the discontinuities reached 9.1 mm in horizontal components, and 26.9 mm in vertical components. The new solution takes into account position discontinuities, and in addition also includes six new stations which were installed after the introduction of the PL-ETRF2000. Therefore, we propose to update the currently-used reference frame for the Polish geodetic primary network (PL-ETRF2000) with the new solution. The new solution was also accepted by the EUREF Technical Working Group as a class A solution (highest accuracy) according to EUREF standards.

La sylviculture d'inspiration systémique: Un saut qualitatif dans l'approche des écosystèmes boisés | Silviculture Inspired by System Theory: A Qualitative Milestone in the Approach of Forest Ecosystems

2000 ◽  
Vol 151 (2) ◽  
pp. 62-65
Author(s):  
Guido Bernasconi
Keyword(s):  
System Theory ◽  
Forest Ecosystems ◽  
Point Of View ◽  
Minimum Constraints ◽  
Different Parts

It is now recognised that the forest is far more than just the sum of its constituent trees, and it should also be realised that it has a particular ability to surprise us with unsuspected characteristics. This new philosophy is grounded in knowledge that focuses on the aggregate rather than on different parts that would have been dissected somewhat arbitrarily. Foresters who espouse this point of view accept that the forest can express itself with minimum constraints and they no longer attempt to subject it to preconceived ideas. Having a certain conception of the creative capabilities of a forest, silviculturists need take only one more step in order to assume new responsibilities: with meticulous care and attention, they will help the forest become more complex by drawing their inspiration from the principles of complementary treatments, biodiversity and consistency.

scholarly journals Erratum to: A consistent combination of GNSS and SLR with minimum constraints

2015 ◽  
Vol 89 (12) ◽  
pp. 1181-1182
Author(s):  
Susanne Glaser ◽  
Mathias Fritsche ◽  
Krzysztof Sośnica ◽  
Carlos Javier Rodríguez-Solano ◽  
Kan Wang ◽  
...  
Keyword(s):  
Minimum Constraints

scholarly journals Minimum constraint removal problem for line segments is NP-hard

2022 ◽  
Author(s):  
Bahram Sadeghi Bigham
Keyword(s):  
Free Path ◽  
Np Hard ◽  
Convex Polygons ◽  
Linear Solution ◽  
Line Segments ◽  
Subset Sum Problem ◽  
Starting Point ◽  
Subset Sum ◽  
Feasible Path ◽  
Minimum Constraints

In the minimum constraint removal ([Formula: see text]), there is no feasible path to move from a starting point towards the goal, and the minimum constraints should be removed in order to find a collision-free path. It has been proved that [Formula: see text] problem is NP-hard when constraints have arbitrary shapes or even they are in shape of convex polygons. However, it has a simple linear solution when constraints are lines and the problem is open for other cases yet. In this paper, using a reduction from Subset Sum problem, in three steps, we show that the problem is NP-hard for both weighted and unweighted line segments.

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