Control of Dynamic Systems via Neural Networks

This report is devoted to the problem of controlling a class of linear time-invariant dynamic systems via controllers based on additive neural network models. In particular, the tracking and stabilization problems are considered. First, we show how to transform the problem of tracking a reference signal by a control system into the stabilization problem. Then, some concepts from the variable structure control theory are utilized to construct stabilizing controllers. In order to facilitate the stability analysis of the closed-loop systems we employ a special state space transformation. This transformation allows us also to reveal connections between the proposed controllers and the additive neural network models

ON SOLVING CONSTRAINED OPTIMIZATION PROBLEMS WITH NEURAL NETWORKS : A PENALTY FUNCTION METHOD APPROACH

This paper is concerned with utilizing analog circuits to solve various linear and nonlinear programming problems. The dynamics of these circuits are analyzed. Then, the previously proposed circuit implementations for solving optimization problems are examined. A new nonlinear programming network and its circuit implementation is then introduced which utilizes the nonlinearities to eliminate the problems encountered in previous circuit implementations

PENGARUH TERENDAMNYA PERKERASAN ASPAL OLEH AIR LAUT YANG DITINJAU TERHADAP KARAKTERISTIK MARSHALL

Perkerasan jalan yang berada di pesisir pantai berpotensi digenangi oleh air laut. Kadar garam adalah salah satu yang membedakannya dengan air tawar. Garam-garamman yang terdapat dalam air laut adalah klorida (55%), natrium (31%), sulfat (8%), magnesium (4%), kalsium (!%), dan sisanya (< 1%) bikarbonat, bromide, asam borak, strontium, dan florida. Jadi, rata-rata dalam 1 liter air laut terdapat 3,5% kadar garam. Berdasarkan SNI 2010 Revisi 2 Kementerian Pekerjaan Umum Direktorat Jenderal Bina Marga, nilai Marshall Test untuk lapis aspal beton AC-WC adalah minimal 800 kg untuk stabilitas dan minimal 3 mm untuk kelelehan plastisnya., jadi untuk Marshall Quotientnya minimal 250 kg/mm. Penelitian ini menggunakan material batu pecah yang berasal dari daerah Lolak, Kotamobagu. Penelitian ini bersifat kajian dilaboratorium, dimulai dengan pemeriksaan sifat-sifat fisik terhadap material batu pecah, agregat kasar, agregat sedang, dan abu batu. Kemudian dilakukan perhitungan kadar aspal perkiraan dan didapatkan sebesar 5,8% yang kemudian divariasikan mulai 3,8%, 4,8%, 5,8%, 6,8%, 7,8% untuk mendapatkan nilai kadar aspal terbaik dari pengujian Marshall. Nilai kadar aspal terbaik digunakan untuk pembuatan benda uji yang akan digunakan untuk perendaman air laut dengan durasi perendaman 24 jam dan 48 jam, variasi suhu perendaman 25°C, 30°C, 35°C, 40°C, dan variasi kadar garam 3,5% (air laut), yang kemudian ditambahkan garam dapur sebesar 0,5% per 1 liter air laut yang menjadi 4,0% dan 4,5%. Kemudian akan dibandingkan dengan perendaman air tawar yang variasi durasi dan suhu yang sama dengan perendaman air laut. Hasil yang di dapatkan dari pengujian Marshall dapat disimpulkan bahwa air laut lebih merusak dibandingkan air tawar dengan perbandingan nilai stabilitas yang mencapai 6,59% untuk durasi 24 jam dan 29,90% untuk durasi 48 jam. Pada nilai kelelehan plastisnya terjadi peningkatan dari 6,16 mm pada perendaman air tawar menjadi 7,24 mm pada perendaman air laut. Nilai Marshall Quotientnya mengalami penurunan 8,88% - 20,06% untuk durasi 24 jam dan 14,10% - 41,39% untuk durasi 48 jam.   Kata kunci : Air Laut, Lapis Aspal Beton AC-WC,Marshall Tes

Transformações do nitrogênio no solo após adição de dejeto líquido e cama sobreposta de suínos

O objetivo deste trabalho foi avaliar as transformações do N no solo após a aplicação de dejeto líquido (DLS) e cama sobreposta (CSS) de suínos, com e sem palha de aveia, e com e sem incorporação ao solo. Os tratamentos avaliados foram: solo (S), S + palha incorporada (S + Pi), S + palha em superfície (S + Ps), S + CSS incorporada (S + CSSi), S + CSS em superfície (S + CSSs), S + DLS incorporado (S + DLSi), S + DLS em superfície (S + DLSs), S + Pi + DLSi e S + Ps + DLSs. Avaliaram-se a volatilização de amônia, a nitrificação e a mineralização do N do DLS e da CSS. A incorporação do DLS reduziu a volatilização de amônia em 93%, em comparação à aplicação na superfície do solo. O N amoniacal da CSS foi nitrificado nos cinco primeiros dias. A taxa de nitrificação líquida foi duas vezes maior com a incorporação do DLS ao solo do que na superfície. A mineralização do N orgânico não diferiu com o modo de aplicação do DLS e da CSS no solo. Na CSS, 14,6% do N foi mineralizado, contra 34,9% no DLS. A aplicação do DLS com a palha de aveia na superfície do solo favorece a imobilização microbiana de N, mas não reduz as perdas de N por volatilização de amônia

Outcomes of elective liver surgery worldwide: a global, prospective, multicenter, cross-sectional study

Background: The outcomes of liver surgery worldwide remain unknown. The true population-based outcomes are likely different to those vastly reported that reflect the activity of highly specialized academic centers. The aim of this study was to measure the true worldwide practice of liver surgery and associated outcomes by recruiting from centers across the globe. The geographic distribution of liver surgery activity and complexity was also evaluated to further understand variations in outcomes. Methods: LiverGroup.org was an international, prospective, multicenter, cross-sectional study following the Global Surgery Collaborative Snapshot Research approach with a 3-month prospective, consecutive patient enrollment within January–December 2019. Each patient was followed up for 90 days postoperatively. All patients undergoing liver surgery at their respective centers were eligible for study inclusion. Basic demographics, patient and operation characteristics were collected. Morbidity was recorded according to the Clavien–Dindo Classification of Surgical Complications. Country-based and hospital-based data were collected, including the Human Development Index (HDI). (NCT03768141). Results: A total of 2159 patients were included from six continents. Surgery was performed for cancer in 1785 (83%) patients. Of all patients, 912 (42%) experienced a postoperative complication of any severity, while the major complication rate was 16% (341/2159). The overall 90-day mortality rate after liver surgery was 3.8% (82/2,159). The overall failure to rescue rate was 11% (82/ 722) ranging from 5 to 35% among the higher and lower HDI groups, respectively. Conclusions: This is the first to our knowledge global surgery study specifically designed and conducted for specialized liver surgery. The authors identified failure to rescue as a significant potentially modifiable factor for mortality after liver surgery, mostly related to lower Human Development Index countries. Members of the LiverGroup.org network could now work together to develop quality improvement collaboratives

OUTPUT FEEDBACK VARIABLE STRUCTURE CONTROLLERS AND STATE ESTIMATORS FOR UNCERTAIN DYNAMIC SYSTEMS

In this paper we propose a new class of output feedback variable structure controllers and state estimators (observers) for uncertain dynamic systems with hounded uncertainties. No statistical information about the uncertain elements is assumed. A variable structure systems (VSS) approach together with the geometric approach to the analysis and synthesis of system zeros are employed in the synthesis of the proposed output feedback controllers and state estimators. The role of system zeros in the output feedback stabilization and state estimation, using the VSS approach, is discussed. Numerical examples included illustrate the feasibility of the proposed stabilization and state estimation schemes