scholarly journals Sharp degree bounds for sum-of-squares certificates on projective curves

2019 ◽  
Vol 129 ◽  
pp. 61-86 ◽  
Author(s):  
Grigoriy Blekherman ◽  
Gregory G. Smith ◽  
Mauricio Velasco
2015 ◽  
Vol 5 (1) ◽  
pp. 11
Author(s):  
Anies Mutiari ◽  
Wiratni Wiratni ◽  
Aswati Mindaryani

Pemurnian biogas telah banyak dilakukan untuk menghilangkan kadar CO2  dan meningkatkan kandungan CH4  yang terkandung di dalamnya. Kandungan CH4 yang tinggi akan memberikan unjuk kerja yang lebih baik. Model  matematis proses adsorpsi CO2 disusun berdasarkan teori lapisan film antar fasa, dimana pada proses yang ditinjau terdapat tiga fase yaitu gas, cair dan padat. Model matematis dari data eksperimental   kecepatan dan kesetimbangan proses adsorpsi CO2 melalui mekanisme pertukaran ion di suatu kolom adsorpsi telah dibuat. Model ini dibuat untuk mencari konstanta yang dapat dipergunakan pada proses scale up data laboratorium ke skala pilot plant. Parameter proses kecepatan yang dicari nilainya adalah koefisien transfer massa massa volumetris CO2 pada fase cair (kLa), koefisien transfer massa volumetris CO2 pada fasegas (kGa) dan tetapan laju reaksi (k1 dan k2). Pada hasil penelitian ini ditunjukkan bahwa nilai parameter yang diperoleh sesuai hasil fitting data dengan model matematis yang digunakan, yaitu model transfer massa pada lapisan film antar fase secara seri: adalah kGa, kla, k1 dan k2  dengan nilai Sum of Squares Error (SSE) rata-rata 0,0431. Perbandingan nilai kGa hasil simulasi dan teoritisnya memberikan kesalahan rata-rata 18,79%. Perbandingan nilai kLa hasil simulasi dan teoritis memberikan kesalahan rata-rata 7,92%.Kata kunci: model matematis, adsorpsi CO2, pemurnian biogas


Author(s):  
MÁTYÁS DOMOKOS ◽  
VESSELIN DRENSKY

AbstractThe problem of finding generators of the subalgebra of invariants under the action of a group of automorphisms of a finite-dimensional Lie algebra on its universal enveloping algebra is reduced to finding homogeneous generators of the same group acting on the symmetric tensor algebra of the Lie algebra. This process is applied to prove a constructive Hilbert–Nagata Theorem (including degree bounds) for the algebra of invariants in a Lie nilpotent relatively free associative algebra endowed with an action induced by a representation of a reductive group.


2021 ◽  
pp. 000313482110111
Author(s):  
Ryan C. Pickens ◽  
Angela M. Kao ◽  
Mark A. Williams ◽  
Andrew C. Herman ◽  
Jeffrey S. Kneisl

Background In response to the COVID-19 pandemic, children’s hospitals across the country postponed elective surgery beginning in March 2020. As projective curves flattened, administrators and surgeons sought to develop strategies to safely resume non-emergent surgery. This article reviews challenges and solutions specific to a children’s hospital related to the resumption of elective pediatric surgeries. We present our tiered reentry approach for pediatric surgery as well as report early data for surgical volume and tracking COVID-19 cases during reentry. Methods The experience of shutdown, protocol development, and early reentry of elective pediatric surgery are reported from Levine’s Children’s Hospital (LCH), a free-leaning children’s hospital in Charlotte, North Carolina. Data reported were obtained from de-identified hospital databases. Results Pediatric surgery experienced a dramatic decrease in case volumes at LCH during the shutdown, variable by specialty. A tiered and balanced reentry strategy was implemented with steady resumption of elective surgery following strict pre-procedural screening and testing. Early outcomes showed a steady thorough fluctuating increase in elective case volumes without evidence of a surgery-associated positive spread through periprocedural tracking. Conclusion Reentry of non-emergent pediatric surgical care requires unique considerations including the impact of COVID-19 on children, each children hospital structure and resources, and preventing undue delay in intervention for age- and disease-specific pediatric conditions. A carefully balanced strategy has been critical for safe reentry following the anticipated surge. Ongoing tracking of resource utilization, operative volumes, and testing results will remain vital as community spread continues to fluctuate across the country.


2020 ◽  
Vol 15 (1) ◽  
pp. 258-265
Author(s):  
Yu Zhou ◽  
Daoguang Mu ◽  
Xinfeng Dong

AbstractS-box is the basic component of symmetric cryptographic algorithms, and its cryptographic properties play a key role in security of the algorithms. In this paper we give the distributions of Walsh spectrum and the distributions of autocorrelation functions for (n + 1)-bit S-boxes in [12]. We obtain the nonlinearity of (n + 1)-bit S-boxes, and one necessary and sufficient conditions of (n + 1)-bit S-boxes satisfying m-order resilient. Meanwhile, we also give one characterization of (n + 1)-bit S-boxes satisfying t-order propagation criterion. Finally, we give one relationship of the sum-of-squares indicators between an n-bit S-box S0 and the (n + 1)-bit S-box S (which is constructed by S0).


2013 ◽  
Vol 23 (3) ◽  
pp. 1398-1423 ◽  
Author(s):  
Dávid Papp ◽  
Farid Alizadeh
Keyword(s):  

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