Hasil Pencarian  ::  Simpan CSV :: Kembali

Abstrak :
Dalam tesis ini diajukan sistem gabungan multicarrier code-division multiple-access (Multicarrier CDMA) dengan skema Pure Aloha (P-Aloha) dan Slotted Aloha (S-Aloha), yang disebut multicarrier CDMA P-Aloha dan multicarrier CDMA S-Aloha. Analisa terhadap kedua sistem dilakukan terhadap salah satu parameter kinerja sistem yaitu throughput. Dalam sistem multicarrier CDMA P-Aloha dan multicarrier CDMA S-Aloha, data mula-mula dikonversi dari serial menjadi paralel. Data tersebut kemudian dimodulasi dengan direct sequence spread-spectrum (DS-SS) menggunakan kode penyebar yang spesifik pada setiap user, dan semua sinyal DS tersebut ditransmisikan secara paralel pada subcarrier yang berbeda-beda. Setelah dikodekan, data dikirim secara acak untuk sistem multicarrier CDMA P-Aloha, sedangkan pada multicarrier CDMA S-Aloha data dikirim pada permulaan time-slot sesuai mekanisme sistem S-Aloha. Hasil penelitian menunjukkan bahwa kedua sistem memiliki throughput yang tinggi untuk transmisi sinyal dengan laju tinggi, dan multicarrier CDMA S-Aloha memiliki throughput yang lebih tinggi daripada multicarrier CDMA P-Aloha. Hasil penelitian juga menunjukkan bahwa throughput kedua sistem semakin tinggi dengan meningkatnya jumlah subcarrier dan panjang kode single-carrier yang digunakan, sementara peningkatan panjang subpaket menurunkan throughput kedua sistem. Multicarrier CDMA Aloha memiliki throughput yang lebih baik dari CDMA Aloha.

---

This thesis proposes integrated systems consisting of multicarrier code-division multiple-access (Multicarrier CDMA) with Pure Aloha (P-Aloha) and Slotted Aloha (S-Aloha) schemes, named multicarrier CDMA P-Aloha and multicarrier CDMA S-Aloha, respectively. The performance analysis of both systems is stated as throughput, Multicarrier CDMA Aloha is proposed to improve the performance of CDMA Aloha. In multicarrier CDMA P-Aloha and multicarrier COMA S-Aloha the initial data is serial-to-parallel converted to a number of lower rate data streams. Each stream which consists of a part of the initial data called sub-packet will be then direct sequence spread-spectrum modulated using specific spreading code for each user, and all the DS-SS signals are transmitted in parallel on different subcarriers. The coded data is sent randomly in multicarrier CDMA P-Aloha system, whereas in multicarrier CDMA S-Aloha, the data is sent at the beginning of the time-slot according to the mechanism of S-Aloha system. Results show that both systems have high throughput for high bit rate signal transmission, and multicarrier CDMA S-Aloha outperforms multicarrier CDMA P-Aloha. It is also shown that the throughput of both systems improves as the number of subcarriers and the length of single-carrier code increase, while the increase of subpacket length degrades the throughput of both systems. Multicarrier CDMA Aloha has better performance compared to CDMA Aloha.

Abstrak :
Rumah kos mahasiswa yang terletak di kawasan padat penduduk berpotensi terdampak kebisingan lingkungan hingga melampaui standar kebisingan. Hal ini dapat berpengaruh negatif pada kesehatan fisik dan mental mahasiswa di dalam kamar kos. Fasad sebagai lapisan pelindung paling luar pada bangunan perlu ditinjau perannya dalam mengurangi kebisingan. Skripsi ini bertujuan untuk mengetahui gangguan kebisingan lingkungan dan elemen fasad apa yang paling berperan dalam pengendalian kebisingan yang memasuki kamar kos. Kebisingan dapat merambat melalui medium udara lalu mengalami pemantulan, penyerapan, dan penerusan pada saat menyentuh bidang padat seperti fasad rumah kos. Kemampuan fasad dalam mengurangi transmisi kebisingan dapat dipengaruhi oleh elemen fasad seperti jenis material, bukaan, dan bentuk geometri selubung bangunan. Penulisan ini menganalisis elemen fasad rumah kos pada kawasan padat penduduk dan ramai lalu lintas di Jalan Haji Amat Kukusan, Depok sebagai objek studi. Analisis dilakukan berdasarkan pengukuran tingkat kebisingan lingkungan, perhitungan nilai reduksi kebisingan, dan perhitungan persentase elemen fasad rumah kos. Hasil analisis studi kasus menunjukkan bahwa fasad rumah kos terbukti dapat mengurangi kebisingan secara signifikan namun beberapa sampel rumah kos belum dapat mereduksi kebisingan lingkungan hingga mencapai batas standar kebisingan. Elemen yang paling berperan terhadap kemampuan fasad dalam mengurangi kebisingan adalah elemen bukaan. ......Student boarding houses which are located in densely populated areas have the potential to be affected by environmental noise to the point of exceeding noise standards. This can negatively affect the physical and mental health of students in boarding rooms. The facade as the outermost protective layer in a building needs to be reviewed for its role in reducing noise. This thesis aims to find out which environmental noise disturbances and facade elements play the most role in controlling noise that enters the boarding house. Noise can travel through the air medium and then experience reflection, absorption, and transmission when it hits a solid surface, such as the facade of a boarding house. The facade's ability to reduce noise transmission can be affected by facade elements such as the type of material, openings, and the overall geometry of the building. This writing analyzes the elements of the facade of a boarding house in a densely populated and busy traffic area on Jalan Haji Amat Kukusan, Depok as an object of study. The analysis was carried out based on measuring environmental noise levels, calculating noise reduction values, and calculating the percentage of the student boarding houses’ elements. The results of the case study analysis show that the facade of the boarding house is proven to be able to reduce noise significantly, but several boarding house samples have not been able to reduce environmental noise down to the noise standard limit. The elements that play the most role to the facade's ability to reduce noise are the building openings.

Abstrak :
This book puts the focus on serving human listeners in the sound field synthesis although the approach can be also exploited in other applications such as underwater acoustics or ultrasonics. The author derives a fundamental formulation based on standard integral equations and the single-layer potential approach is identified as a useful tool in order to derive a general solution. He also proposes extensions to the single-layer potential approach which allow for a derivation of explicit solutions for circular, planar, and linear distributions of secondary sources. Based on above described formulation it is shown that the two established analytical approaches of Wave Field Synthesis and Near-field Compensated Higher Order Ambisonics constitute specific solutions to the general problem which are covered by the single-layer potential solution and its extensions.