Studi Eksperimen Pengiriman Sinyal Video Real-Time dengan Aplikasi Skype Mobile pada Jaringan Nirkabel 802.11 di Tengah Interferensi Kepadatan Lalu Lintas Manusia

Penggunaan mobile phone sebagai alat komunikasi sangat demikian pesat peningkatan pengguna serta beragam jenis fungsi yang terdapat didalamnya. Diantara dari sekian banyak aplikasi yang terdapat pada mobile phone adalah Skype berbasis mobile phone OS yang digunakan untuk telekonferensi. Hal yang tidak bisa dilepaskan dari aplikasi ini adalah dibutuhkannya akses jaringan internet yang mumpuni agar aplikasi ini dapat dirasakan maksimal fungsinya. Wi-fi merupakan salahsatu akses internet yang lazim digunakan masyarakat saat ini. Banyak faktor yang menyebabkan akses pada internet yang tersedia tidak selalu memberikan performa yang terbaik, satu diantaranya adalah interferensi. Pada penelitian ini dilakukan sebuah uji coba berupa transmisi sinyal video secara real-time dengan menggunakan aplikasi pada mobile phone yaitu Skype mobile phone OS. Skype ini dijalankan pada jaringan internet wi-fi, yang dipengaruhi atau diinterferensi oleh kehadiran objek (berupa lalu lintas manusia) di sekitar jaringan tersebut. Wireshark digunakan untuk mendapatkan data keandalan jaringan wi-fi yang digunakan atau dikenal dengan QoS. Pada sisi lain EvalVid digunakan untuk mendapatkan data QoE yang dibatasi hanya mendapatkan data PSNR (Peak Signal to Noise Ratio). Video delay time diperhitungkan sebagai acuan kepuasan end user dalam menggunakan layanan konferensi video. Hasil penelitian menunjukan bahwa kepadatan karyawan di dalam ruangan dapat memberikan pengaruh terhadap nilai QoS dan QoE jika kepadatan karyawan itu disertai dengan lalu-lintas karyawan di dalam ruangan tersebut. Namun jika kepadatan karyawan tidak disertai dengan lalu-lintas di dalamnya maka kepadatan karyawan itu sendiri tidak memberikan pengaruh pada parameter yang diukur

A variable streamflow velocity method for global river routing model: model description and preliminary results

International audienceThis paper presents an attempt of simulating daily fluctuations of river discharge at global scale. Total Runoff Integrating Pathways (TRIP) is a global river routing model which can help to isolate the river basins, inter-basin transport of water through river channels, as well as collect and route runoff to the river mouths for all the major rivers. In the previous version of TRIP (TRIP 1.0), a simple approach of constant river flow velocity is used. In general, that approach is sufficient to model mean long-term discharges. However, to model short-term fluctuations, more sophisticated approach is required. In this study, we implement a variable streamflow velocity method to TRIP (TRIP 2.0) and validate the new approach over the world's 20 major rivers. Two numerical experiments, one with the TRIP 1.0 and another with TRIP 2.0 are performed. Input runoff is taken from the multi-model product provided by the second Global Soil Wetness Project. For the rivers which have clear daily fluctuations of river discharge, TRIP 2.0 shows advantages over TRIP 1.0, suggesting that TRIP 2.0 can be used to model flood events

Deriving a global river network map and its sub-grid topographic characteristics from a fine-resolution flow direction map

This paper proposes an improved method for converting a fine-resolution flow direction map into a coarse-resolution river network map for use in global river routing models. The proposed method attempts to preserve the river network structure of an original fine-resolution map in the upscaling procedure, as this has not been achieved with previous upscaling methods. We describe an improved method in which a downstream cell can be flexibly located on any cell in the river network map. The improved method preserves the river network structure of the original flow direction map and allows automated construction of river network maps at any resolution. Automated construction of a river network map is helpful for attaching sub-grid topographic information, such as realistic river meanderings and drainage boundaries, onto the upscaled river network map. The advantages of the proposed method are expected to enhance the ability of global river routing models by providing ways to more precisely represent surface water storage and movement

Hubungan antara Penyesuaian Diri dan Dukungan Sosial terhadap Stres Lingkungan pada Santri Baru

Penelitian ini bertujuan untuk mengetahui adanya hubungan antara penyesuaian diri dan dukungan sosial dengan stres lingkungan pada santri baru di Pondok Pesantren. Metode penelitian menggunakan metode kuantitatif. metode pengumpulan data menggunakan skala penyesuaian diri dan skala dukungan sosial serta stres lingkungan. Metode analisis data dengan menggunakan teknik analisis regresi.Subjek penelitian adalah santri baru yang mengikuti pembelajaran di Pondok Pesantren. Kelas satu Madrasah Tsanawiyah dan kelas satu Madrasah Aliyah. Penelitian dilaksanakan dengan subjek sebanyak 46 orang dengan menggunakan teknik populatif. Teknik analisis data yang digunakan adalah teknik analisis dua prediktor dengan bantuan program Statistical Product and Service Solution (SPSS) for Windows 19.0

Downscaled Rainfall Prediction Model (DRPM) using a Unit Disaggregation Curve (UDC)

International audienceThis study was undertaken to identify the process for generating finer time scaled rainfall from higher time scaled data. The Downscaled Rainfall Prediction Model (DRPM) using the technique of unit disaggregation curve (UDC) was developed under the concept of coupling the stochastic autoregressive (AR) model with a wavelet filter and disaggregation model. Sequences of the number of rainy days and monthly rainfall were simulated from 52-year rainfall records at 4 stations in the northeastern part of Thailand. Compared with actual rainfall sequences, the 30 year generated sequences provided R-square values of 0.47-0.60. The model was applied to forecast the number of rainy days and monthly rainfall for the year of 2002. When compared with actual records the prediction model provided R-square values of 0.50 to 0.79

An integrated model for the assessment of global water resources ? Part 2: Anthropogenic activities modules and assessments

International audienceTo assess global water resources from the perspective of subannual variation in water resources and water use, an integrated water resources model was developed. In a companion report, we presented the global meteorological forcing input used to drive the model and two natural hydrological cycle modules, namely, the land surface hydrology module and the river routing module. Here, we present the remaining four modules, which represent anthropogenic activities: a crop growth module, a reservoir operation module, an environmental flow requirement module, and an anthropogenic withdrawal module. In addition, we discuss the results of a global water resources assessment using the integrated model. The crop growth module is a relatively simple model based on heat unit theory and potential biomass and harvest index concepts. The performance of the crop growth module was examined extensively because agricultural water comprises approximately 70% of total water withdrawal in the world. The estimated crop calendar showed good agreement with earlier reports for wheat, maize, and rice in major countries of production. The estimated irrigation water withdrawal also showed fair agreement with country statistics, but tended to underestimate countries in the Asian monsoon region. In the reservoir operation module, 452 major reservoirs with more than 1 km³ each of storage capacity store and release water according to their own rules of operation. Operating rules were determined for each reservoir using an algorithm that used currently available global data such as reservoir storage capacity, intended purposes, simulated inflow, and water demand in the lower reaches. The environmental flow requirement module was newly developed based on case studies from around the world. The integrated model closes both energy and water balances on land surfaces. Global water resources were assessed on a subannual basis using a newly devised index that locates water-stressed regions that were undetected in earlier studies. These regions, which are indicated by a gap in the subannual distribution of water resources and water use, include the Sahel, the Asian monsoon region, and southern Africa. The integrated model is applicable to assess various global environmental projections such as climate change