29 research outputs found
Vertical Handover Management for VoIP Session over Brodband Wireless Networks
Today, wireless LAN (IEEE802.11g/n) has been the dominant wireless network that can provide high data rates in a \ud
limited coverage area. While emerging mobile WiMAX (IEEE802.16e) can provide a wireless broadband access to \ud
mobile users in a wide coverage area. These two different technolgies will co-exist while complementing each other in \ud
some regions, hence, a mobile node (MN) with dual interfaces traverses and executes many handovers (HOs) between \ud
802.11g and 802.16e. Meanwhile, there is a huge demand for Voice over IP (VoIP) service over wireless networks. \ud
However, VoIP is a delay and loss sensitive application, hence, VoIP session is more likely to be deteriorated during \ud
HO between 802.11g and 802.16e. In order to maintain quality of VoIP session during HO, we proposed Vertical \ud
Handover Management (VHM) for VoIP session that focuses on HO initiation and decision strategy according to the \ud
wireless link condition and congestion state of wireless networks. The VHM exploits request to send (RTS) retries and \ud
round trip time (RTT) between an MN and an access point in an 802.11g interface as well as a carrier to interference \ud
noise ration (CINR) level and MN???s queue length of an 802.16e interface as HO triggers. We then conducted simulation \ud
experiments to evaluate the effectiveness of our proposed VHM using QualNet 4.5. Our simulation results show that \ud
our proposed VHM can preserve the quality of VoIP session during such HO
A Low Cost Wearable Medical Device for Vital Signs Monitoring in Low-Resource Settings
Medical devices are often expensive, so people in low-income countries cannot afford them. This paper presents the design of a low-cost wearable medical device to measure vital signs of a patient including heart rate, blood oxygen saturation level (SpO2) and respiratory rate. The wearable medical device mainly consists of a microcontroller and two biomedical sensors including airflow thermal sensor to measure respiratory rate and pulse oximeter sensor to measure SpO2 and heart rate. We can monitor the vital signs from a smartphone using a web browser through IEEE802.11 wireless connectivity to the wearable medical device. Furthermore, the wearable medical device requires simple management to operate; hence, it can be easily used. Performance evaluation results show that the designed wearable medical device works as good as a standard SpO2 device and it can measure the respiratory rate properly. The designed wearable medical device is inexpensive and appropriate for low-resource settings. Moreover, as its components are commonly available in the market, it easy to assembly and repair locally
Evaluation of Academic Information System Using Delone and Mclane Success Model: A Case Study ff Academic Information System Hasanuddin University
This study examines the effectiveness of the utilization (individual impact) of academic information systems at Hasanuddin University using the DeLone and McLean information system success model. This model has seven hypotheses to examine the construct relationships including system quality predicts user satisfaction (H1), information quality predicts user satisfaction (H2), system quality predicts actual use (H3), information quality predicts actual use (H4), user satisfaction predicts actual use (H5a), actual use predicts user satisfaction (H5b), user satisfaction predicts individual impact (H6), and actual use predicts individual impact (H7). We use structural equation modeling with Partial Least Square technique. The results show that H1, H2, H6, H7 have a significant positive impact and the remaining hypothesis have no significant positive impact. In conclusion, indicators that influence the effectiveness of using the system are on the system quality variable and the quality of information with the greatest influence on the quality of information
Evaluasi dan Optimisasi Model Routing pada Delay Tolerant Network (DTN) untuk Pengiriman Data ke Desa Terpencil
Delay Tolerant Network (DTN) merupakan arsitektur jaringan end-to-end yang didesain untuk menyediakan komunikasi pada lingkungan dengan konektivitas intermittent, penundaan yang besar, dan error rate yang tinggi. Penelitian ini bertujuan untuk mengevaluasi dan mengoptimisasi model routing pada DTN yang digunakan untuk pengiriman data ukuran besar ke desa terpencil yang tidak memiliki infrastruktur jaringan telekomunikasi yang memadai. Hasil evaluasi 6 model routing standar pada DTN, didapatkan model routing yang paling banyak mengirimkan pesan untuk skenario Makassar-Selayar adalah Direct Delivery Router (DDR), Spray & Wait (SWR), dan MaxProp (MPR). Optimisasi DDR dengan cara menggabungkan DDR dengan Oracle Based Routing menghasilkan model routing baru yang disebut dengan Direct Oracle Router (DOR). Hasil penelitian menunjukkan bahwa DOR memiliki kemampuan untuk mengirimkan pesan lebih banyak dibandingkan dengan model routing lain, hal ini dapat dilihat dari probabilitas penerimaan pesan yang lebih tinggi dibandingkan dengan model lain. Meskipun DOR memiliki latency yang lebih tinggi dibandingkan dengan DDR untuk pengiriman file ukuran 25 MB, namun untuk ukuran file 75 MB ??? 100 MB, DOR memiliki latency yang lebih rendah
Performance Evaluation of Microservices Communication with REST, GraphQL, and gRPC
Microservice architecture has become the design paradigm for creating scalable and maintainable software sys- tems. Selecting the proper communication protocol in microser- vices is critical to achieving optimal system performance. This study compares the performance of three commonly used API protocols: REST, GraphQL, and gRPC, in microservices ar- chitecture. In this study, we established three microservices implemented in three containers and each microservice contained a Redis and MySQL database. We evaluated the performance of these API protocols using two key performance metrics: response time and CPU Utilization. This study performs two distinct data retrieval: fetching flat data and fetching nested data, with a number of requests ranging from 100 to 500 requests. The experimental results indicate that gRPC has a faster response time, followed by REST and GraphQL. Moreover, GraphQL shows higher CPU Utilization compared to gRPC and REST. The experimental results provide insight for developers and architects seeking to optimize their microservices communication protocols for specific use cases and workloads
Meningkatkan Kinerja Java Virtual Machine dengan Mengoptimalkan Peran Garbage Collector
Pada penelitian ini, kinerja Java Virtual Machine (JVM) dalam mengeksekusi aplikasi Java berusaha ditingkatkan dengan cara mengoptimalkan peran Garbage Collector (GC). GC adalah salah satu komponen di dalam JVM yang bertugas untuk mencari obyek-obyek Java yang sudah tidak digunakan lagi oleh program (garbage) tapi masih menempati ruang pada memori. Selanjutnya GC akan membersihkan ruang memori tersebut untuk digunakan oleh obyek Java yang baru. JVM secara otomatis menjalankan GC jika ruang memori yang tersedia tidak cukup lagi untuk menampung obyek baru yang dibuat oleh Java aplikasi. Untuk mengoptimalkan peran GC dalam meningkatkan kinerja JVM, GC tidak hanya difungsikan untuk membersihkan ruang memori dari garbage, tapi juga difungsikan untuk mengubah urutan-urutan obyek yang masih digunakan oleh program di memori, sedapat mungin menyesuaikan dengan cara program mengakses obyek-obyek tersebut. Hal ini dimaksudkan agar prosessor komputer lebih cepat mendapatkan data dari memori sehingga eksekusi program menjadi lebih cepat. Hasil penelitian ini menunjukkan bahwa dengan urutan-urutan obyek yang tepat, kinerja JVM meningkat, ditandai dengan waktu eksekusi aplikasi Java yang menjadi lebih singkat
DESAIN DAN IMPLEMENTASI TEKNOLOGI MOBILE BACKEND AS A SERVICE(MBaaS) PADA APLIKASI LAYANAN WEB
Penelitian ini bertujuan untuk merancang teknologi Mobile Backend as a Sevice dan diterapkan pada jaringan lokal menggunakan layanan web jenis REST.Pada penelitian ini digunakan metode eksperimental dalam pengembangan arsitektur teknologi MBaaS. Sistem dibagi menjadi tiga aplikasi, yaitu aplikasi server, aplikasi lokal dan aplikasi mobile. Sistem diuji menggunakan sistem point of sales (POS) pada restoran atau kafe. Selanjutnya melakukan analisis standar pada jaringan lokal dan metode akses layanan. Pengujian selanjutnya adalah uji response time dan uji kinerja dari fitur aplikasi.Hasil penelitian ini menunjukkan bahwa layanan web jenis REST dengan metode akses berbasis CORS serta penggunaan fix IP pada jaringan lokal dapat digunakan untuk membangun MBaaS
Performance evaluation of microservices communication with REST, GraphQL, and gRPC
Microservice architecture has become the design paradigm for creating scalable and maintainable software systems. Selecting the proper communication protocol in microservices is critical to achieving optimal system performance. This study compares the performance of three commonly used API protocols: REST, GraphQL, and gRPC, in microservices architecture. In this study, we established three microservices implemented in three containers and each microservice contained a Redis and MySQL database. We evaluated the performance of these API protocols using two key performance metrics: response time and CPU Utilization. This study performs two distinct data retrieval: fetching flat data and fetching nested data, with a number of requests ranging from 100 to 500 requests. The experimental results indicate that gRPC has a faster response time, followed by REST and GraphQL. Moreover, GraphQL shows higher CPU Utilization compared to gRPC and REST. The experimental results provide insight for developers and architects seeking to optimize their microservices communication protocols for specific use cases and workloads
マルチ ホーム コウタイイキ ムセン アクセス ネットワーク カンキョウ ニ オケル ジツジカン ツウシン ノ タメノ ハンド オーバ カンリ シュホウ
博士(Doctor)工学(Engineering)奈良先端科学技術大学院大学博第897号甲第897号博士(工学)奈良先端科学技術大学院大