Multiresolution modeling and simulation of an air-ground combat application

The High Level Architecture (HLA) establishes a common modeling and simulation framework facilitating interoperability and reuse of simulation components. Since 1996, ONERA (French Aeronautics and Space Research Centre) carries out several studies on HLA in order to gain a better understanding of the underlying mechanisms of HLA implementations. The first critical step of this initiative was to develop our own RTI from the HLA specifications. In order to evaluate the cost of making a transition from legacy simulations to HLA, we first developed an HLA federation simulating an air-ground combat involving a set of aircraft's engaged against a surface to air defense system. Current studies on HLA distributed simulation include security, WAN simulations and multiresolution. Conventional simulations represent entities at just one single level of resolution. Multiresolution representation of entities consists in maintaining multiple and concurrent representations of entities. In this paper we address the problem of how HLA services may allow to achieve multiresolution modeling and simulation. Our goal is not to provide a general framework as a basis for designing simulations of entities at different levels of resolution concurrently. We focus on experience feedback we have obtained by migrating a single level resolution HLA federation to a multi-level resolution federation. The selected application is an air-ground combat simulation involving aggregated patrols of aircraft's engaged against a surface to air defense system. In this paper, we briefly describe the air-ground combat simulation application. We then detail the multiresolution representation of entities (patrols and aircraft's), and discuss the chosen mechanisms allowing triggering aggregation from an entity-level representation, and conversely, triggering disaggregation from an aggregate representation. We focus on the HLA services we have selected to maintain several levels of representation concurrently and on methodological issues in designing multiresolution HLA simulations. We have tackled some difficulties and we propose a new HLA service that should make easier the user's task. This multiresolution management service can be added to our RTI or written by using existing HLA services. Finally, future trends are discussed

Design and implementation of a HLA inter-federation bridge

In this paper, we discuss the design and implementation of a HLA inter-federation bridge. Our works are mainly motivated by the scalability and security problems, but we also consider the use of bridges for interoperability purposes. We describe several bridge topologies, including linear and cyclic inter-federations. We discuss problems raised by bridge federates and the use of different RTI implementations. We detail several solutions, leading to the design and implementation of a bridge prototype. Then we present our current results, and on-going works concerning performance improvements, interoperability, and security purposes

PRISE: An Integrated Platform for Research and Teaching of Critical Embedded Systems

In this paper, we present PRISE, an integrated workbench for Research and Teaching of critical embedded systems at ISAE, the French Institute for Space and Aeronautics Engineering. PRISE is built around state-of-the-art technologies for the engineering of space and avionics systems used in Space and Avionics domain. It aims at demonstrating key aspects of critical, real-time, embedded systems used in the transport industry, but also validating new scientific contributions for the engineering of software functions. PRISE combines embedded and simulation platforms, and modeling tools. This platform is available for both research and teaching. Being built around widely used commercial and open source software; PRISE aims at being a reference platform for our teaching and research activities at ISAE

Running real time distributed simulations under Linux and CERTI

This paper presents some experiments and some results to enforce real time distributed simulations in accordance with the High Level Architecture (HLA). Simulations were run by using CERTI, an open source middleware, as the Run Time Infrastructure (RTI). Models were distributed over computers under various available versions of the 2.6 Linux kernel. Studies and experiments relied on a real case study. The chosen case study was the simulation of an "in formation" flight of observation satellites. This case study brings up some real applicative needs in real time distributed simulations and real configurations of simulators and models. Two simulations of "in formation" flight of satellites were studied. The study consisted in modeling the behaviour of the simulators and in running these models by using various kernel or middleware operating mechanisms and services. Time measurements were performed at each test giving some results on the ability of the simulation to meet its real time requirements

Une application pilote de simulation coopérative distribuée sous HLA (PRF SICODIS)

La modélisation et la simulation sont souvent employées par les chercheurs de l'ONERA, par les organismes de la Défense, par les industriels, pour concevoir et valider les systèmes complexes (systèmes de défense, systèmes d'information et de commandement, systèmes embarqués, etc.). Le Projet de Recherche Fédérateur (PRF)"SICODIS" s'intéresse en particulier aux simulations distribuées à événements discrets

Towards an HLA Run-time Infrastructure with Hard Real-time Capabilities

Our work takes place in the context of the HLA standard and its application in real-time systems context. The HLA standard is inadequate for taking into consideration the different constraints involved in real-time computer systems. Many works have been invested in order to providing real-time capabilities to Run Time Infrastructures (RTI) to run real time simulation. Most of these initiatives focus on major issues including QoS guarantee, Worst Case Transit Time (WCTT) knowledge and scheduling services provided by the underlying operating systems. Even if our ultimate objective is to achieve real-time capabilities for distributed HLA federations executions, this paper describes a preliminary work focusing on achieving hard real-time properties for HLA federations running on a single computer under Linux operating systems. Our paper proposes a novel global bottom up approach for designing real-time Run time Infrastructures and a formal model for validation of uni processor to (then) distributed real-time simulation with CERTI

This is Not New: Addressing America\u27s Maternal Mortality Crisis

This article utilizes an intersectional approach to examine the causes and realities of the dismal state of pregnancy-related healthcare in the United States, highlighting the disparate impact on Black pregnant people. The enslavementand brutalization of Black women in the U.S. demonstrates how American society systematically devalues Black health, especially reproductive health. The impacts of this horrific history persist today, resulting in the American healthcare system utterly failing Black mothers and pregnant people of all gender identities. This article surveys this history and presents policy solutions to improve maternal health outcomes for all, but especially Black individuals, including proposed pieces of legislation, implicit bias training, and stricter standards for data collection

Komitmen Pensyarah Institusi Pendidikan Tinggi Swasta Bertaraf Universiti Terhadap Organisasi

Kajian ini bertujuan untuk menentukan tahap dan faktor-faktor yang berkaitan dengan komitmen pensyarah lnstiiusi Pendidikan Tinggi Swasta (IPTS) bertaraf universiti terhadap organisasi. Kajian ini juga bertujuan untuk mengenalpasti status persepsi pensyarah IPTS bertaraf universiti terhadap pembolehubah tidak bersandar dan pembolehubah bersandar iaitu komitmen terhadap organisasi serta rnengenalpasti sumbangan pembolehubah tidak bersandar kepada komitmen terhadap organisasi. Populasi kajian merangkumi 457 orang pensyarah di empat buah IPTS bertaraf universiti iaitu Universiti Tenaga Nasional, Universiti Multimedia, Universiti Teknologi Petronas dan Universiti Tun Abdul Razak. Terdapat 332 daripada 457 set soal selidik yang diedarkan kepada pensyarah IPTS bertaraf universiti yang dapat digunakan untuk analisis seterusnya. Kajian ini menggunakan lima dimensi pembolehubah tidak bersandar iaitu ciriciri demografi terpilih, dimensi ciri-ciri kerja, dimensi sikap dan amalan pengurusan, dimensi nilai kerja dan dimensi kepemimpinan pentadbir serta satu pembolehubah bersandar iaitu komitmen terhadap organisasi. Aspek-aspek di dalam ciri-ciri dernografi terpilih adalah umur, jangka masa perkhidmatan dengan organisasi kini, jangka masa perkhidmatan dengan organisasi lain dan pendapatan. Aspek-aspek di dalam dimensi ciri-ciri ke rja adalah seperti identiti kerja, keragaman kemahiran, autonomi kerja, maklum balas kerja dan kerumitan kerja. Bagi dimensi sikap dan amalan pengurusan, terdapat enam aspek di daiam dimensi tersebut iaitu sikap kumpulan kerja terhadap organisasi, harapan terhadap pencapaian, cabaran kerja, kepentingan sumbangan pensyarah, keutuhan imej kendiri dan amalan pengurusan. Terdapat dua aspek di dalam dimensi nilai kerja iaitu nilai kerja intrinsik dan nilai kerja ekstrinsik. Bagi dimensi kepemimpinan pentadbir pula terdapat tiga aspek iaitu pemikiran, hubungan dengan pensyarah dan ciri-ciri tingkah laku dan personaliti pentadbir. Kajian mendapati status persepsi pensyarah IPTS bertaraf universiti terhadap empat dimensi pembolehubah tidak bersandar menunjukkan tiga aspek dalam dimensi ciri-ciri ke rja berada pada status persepsi yang sederhana memuaskan iaitu keragaman kemahiran, autonomi ke rja dan maklum balas kerja. Dua aspek lagi iaitu identiti kerja dan kerumitan kerja berada pada status persepsi yang memuaskan. Kajian juga mendapati empat aspek dalam dimensi sikap dan amalan pengurusan mendapat status persepsi yang sederhana memuaskan iaitu sikap kumpulan kerja terhadap organisasi, harapan terhadap pencapaian, kepentingan sumbangan pensyarah dan amalan pengurusan, manakala dua aspek lagi dalam dimensi sikap dan amalan pengurusan mendapat status persepsi yang memuaskan iaitu cabaran kerja dan keutuhan imej kendiri. Kedua-dua aspek dalam dimensi nilai kerja iaitu nilai kerja intrinsik dan nilai kerja ekstrinsik mendapat status persepsi yang memuaskan. Kesemua aspek dalam dimensi kepemimpinan pentadbir iaitu pemikiran, hubungan dengan pensyarah dan ciri-ciri tingkah laku dan personaliti adalah berada pada status persepsi yang sederhana memuaskan. Kajian mendapati tahap komitmen pensyarah IPTS terhadap organisasi adalah berada pada tahap sederhana. Dapatan kajian juga mendapati hanya satu aspek dalam ciri-ciri demografi terpilih iaitu jangkamasa perkhidmatan dengan organisasi kini yang mempunyai perkaitan yang bererti dengan komitrnen terhadap organisasi. Kesemua aspek dalam dimensi ciri-ciri kerja mempunyai perkaitan yang positif dan bererti dengan komitmen terhadap organisasi. Begitu juga dengan kesemua aspek dalam dimensi sikap dan amalan pengurusan mempunyai perkaitan yang positif dan bererti dengan komitmen terhadap organisasi. Kedua-dua aspek dalam dimensi nilai kerja iaitu nilai kerja intrinsik dan nilai keja ekstrinsik juga mempunyai perkaitan yang positif dan bererti dengan komitmen terhadap organisasi. Kesemua aspek dalam dimensi kepemimpinan pentadbir didapati tidak rnempunyai perkaitan yang bererti dengan komitrnen terhadap organisasi. Enam aspek dalam pembolehubah tidak bersandar iaitu amalan pengurusan, keragaman kemahiran, nilai ke ja intrinsik, kepentingan sumbangan pensyarah, cabaran keja serta autonomi ke rja menyumbang 41 peratus varians terhadap komitmen terhadap organisasi. Kajian menyarankan bahawa model komitmen terhadap organisasi boleh digunakan sebagai rangka kajian yang sesuai untuk mengkaji komitmen terhadap organisasi dan membentuk suatu model pilihan komitmen terhadap organisasi yang lebih komprehensif dalam konteks di Malaysia. Kajian juga menyarankan beberapa cadangan kepada pihak pentadbir organisasi dan pihak pensyarah dalam usaha untuk meningkatkan komitrnen pensyarah IPTS bertaraf universiti terhadap organisasi. Kajian ini juga mencadangkan bahawa kajian pada masa akan datang harus meliputi semua kumpulan pensyarah di IPTS bertaraf kolej dan kolej universiti serta kumpulan pensyarah di lnstitusi Pengajian Tinggi Awam (IPTA)

Keselarasan Personaliti-Persekitaran Holland dan Hubungannya Dengan Kepuasan Belajar dan Pencapaian Akademik di Kalangan Pelajar Universiti

Tujuan utama kajian ini ialah untuk meninjau pola personaliti pelajar dan rnendefinisi pola persekitaran program pengajian. Kajian ini juga ingin melihat hubungan antara keselarasan personaliti-persekitaran dengan kepuasan belajar dan pencapalan akademik dikalangan pelajar universiti. Teori Tipologi Kerjaya Holland (1973, 1985) dijadikan teori rujukan utama untuk kajian ini menegaskan bahawa semakin tinggi keselarasan personaliti-persekitaran, semakin tinggi tahap pencapaian akademik dan kepuasan belajar. Subjek kajian terdiri daripada pelajar-pelajar Universiti Pertanian Malaysia yang dibahagikan kepada dua kumpulan. Kumpulan pertama terdiri daripada 754 orang pelajar tahun empat iaitu 406 orang pelajar lelaki dan 348 orang pelajar perempuan yang digunakan untuk kajian deskriptif menggunakan teknik EAT

HLA high performance and real-time simulation studies with CERTI

Our work takes place in the context of the HLA standard and its application in real-time systems context. Indeed, current HLA standard is inadequate for taking into consideration the different constraints involved in real-time computer systems. Many works have been invested in order to provide real-time capabilities to Run Time Infrastructures (RTI). This paper describes our approach focusing on achieving hard real-time properties for HLA federations through a complete state of the art on the related domain. Our paper also proposes a global bottom up approach from basic hardware and software basic requirements to experimental tests for validation of distributed real-time simulation with CERTI