Drive to Work or Work to Drive?
(source : Courtney M Cobbs to the group “Public Transportation Supporters”)
Berikut ini adalah prosedur-prosedur perhitungan dan cara analisis perilaku lalulintas di simpang bersinyal dengan menggunakan software KAJI 1997.
Download di sini.
Disadur dari okezone.com
Data Teknis Heli Nahas di Bogor
Sabtu, 13 Juni 2009 – 06:16 wib
JAKARTA – Jatuhnya helikopter milik TNI AU jenis Puma di Lanud Atang Sanjaya, Bogor, cukup menghenyakkan kembali banyak kalangan dan masyarakat. Pasalnya, berita jatuhnya heli di Cianjur masih hangat dalam ingatan.
Berbagai pertanyaan masih hinggap di benak banyak kalangan terkait penyebab heli buatan Perancis tersebut jatuh. Ketidaklaikan heli untuk melakukan penerbangan semakin menguat.
Berikut data teknis heli yang diperoleh:
|Tanggal kejadian||: Jumat, 12 Juni 2009|
|Pukul||: 14.13 WIB|
|Tempat Kejadian||: Lanud Atang Sanjaya Bogor|
|Type Pesawat||: SA-330 PUMA|
|Tile Number||: HT 3306|
|Kesatuan||: Skadron Udara 8 lanud ATS Bogor|
|Misi||: Tes Flight|
|Rute Penerbangan||: ATS – LOC – ATS|
|Awak Pesawat||: 1. Mayor Pnb Sobic (pilot) alm|
|2. Lettu Pnb Wisnu (co Pilot) alm|
|3. Lettu Tek Ronny (Teknisi)|
|4. Serka Catur H (Jmu I) alm|
|5. Serka Efram (Jmu II)|
|6. Serka Ferdinand (Pjmu I)|
|7. Serda Dodi H (Spec) alm|
|Kondisi pesawat||: Rusak berat|
|Korban||: 1. Mayor Pnb Sobic (meninggal)|
|2. Lettu Pnb Wisnu (meninggal)|
|3. Serka Catur H (meninggal)|
|4. Serda Dodi H (meninggal)|
|5. 3 orang lainnya luka berat|
|Type||: SA-330 PUMA|
|Kegunaan||: Multi Purpose|
|Mesin||: Tumo IV C|
|Pabrik Mesin||: Perancis|
|Tahun Pembuatan||: 1977|
|Dioperasikan TNI AU||: 1978|
|Panjang M/R blade||: 7,5 m (24,6 ft)|
|Diameter putaran M/R||: 18.217 m 959.77 ft)|
|Lebar M/R blade||: 60 cm|
|Tinggi pesawat||: 4.535 m (14.87 ft)|
|Panjang pesawat dari nose||: 14.822 m (48.5 ft)|
|Diameter putaran T/R||: 3.042 m (10 ft)|
|Jumlah awak pesawat||: VFR 1 Pilot, IFR 2 Pilot|
|Kemampuan muat barang||: 1500 Kg/ di dalam cabin|
|Kemampuan muat personel||: – 10 orang VIP/VVIP|
|– 16 orang pasanger|
|Kemampuan evakuasi||: 4 pasien tidur, 2 duduk|
|Berat kosong||: 4200 Kg|
|Max take off weight||: 7400 kg|
|Bahan bakar||: Avtur JP-1|
|Kecepatan jelajah||: 120 Kts|
|Kecepatan maksimum||: 167 Kts|
|Maksimum ketinggian||: 16.500 feet|
|Jarak terbang||: 270 nm|
(Sumber : okezone.com, gambar dari http://www.militaryfactory.com)
Countless hours are lost in traffic jams every year. Most frustrating of all are those jams with no apparent cause — no accident, no stalled vehicle, no lanes closed for construction.
Such phantom jams can form when there is a heavy volume of cars on the road. In that high density of traffic, small disturbances (a driver hitting the brake too hard, or getting too close to another car) can quickly become amplified into a full-blown, self-sustaining traffic jam.
A team of MIT mathematicians has developed a model that describes how and under what conditions such jams form, which could help road designers minimize the odds of their formation. The researchers reported their findings May 26 in the online edition of Physical Review E.
Key to the new study is the realization that the mathematics of such jams, which the researchers call “jamitons,” are strikingly similar to the equations that describe detonation waves produced by explosions, says Aslan Kasimov, lecturer in MIT’s Department of Mathematics. That discovery enabled the team to solve traffic jam equations that were first theorized in the 1950s.
The equations, similar to those used to describe fluid mechanics, model traffic jams as a self-sustaining wave. Variables such as traffic speed and traffic density are used to calculate the conditions under which a jamiton will form and how fast it will spread.
Once such a jam is formed, it’s almost impossible to break up — drivers just have to wait it out, says Morris Flynn, lead author of the paper. However, the model could help engineers design roads with enough capacity to keep traffic density low enough to minimize the occurrence of such jams, says Flynn, a former MIT math instructor now at the University of Alberta.
The model can also help determine safe speed limits and identify stretches of road where high densities of traffic — hot spots for accidents — are likely to form.
Flynn and Kasimov worked with MIT math instructors Jean-Christophe Nave and Benjamin Seibold and professor of applied mathematics Rodolfo Rosales on this study.
The team tackled the problem last year after a group of Japanese researchers experimentally demonstrated the formation of jamitons on a circular roadway. Drivers were told to travel 30 kilometers per hour and maintain a constant distance from other cars. Very quickly, disturbances appeared and a phantom jam formed. The denser the traffic, the faster the jams formed.
“We wanted to describe this using a mathematical model similar to that of fluid flow,” said Kasimov, whose main research focus is detonation waves. He and his co-authors found that, like detonation waves, jamitons have a “sonic point,” which separates the traffic flow into upstream and downstream components. Much like the event horizon of a black hole, the sonic point precludes communication between these distinct components so that, for example, information about free-flowing conditions just beyond the front of the jam can’t reach drivers behind the sonic point. As a result, drivers stuck in dense traffic may have no idea that the jam has no external cause, such as an accident or other bottleneck. Correspondingly, they don’t appreciate that traffic conditions are soon to improve and drive accordingly.
“You’re stuck in traffic until all of the sudden it just clears,” says Morris.
In future studies, the team plans to look more detailed aspects of jamiton formation, including how the number of lanes affects the phantom traffic jams.
The research was funded by the U.S. Air Force Office of Scientific Research, the National Science Foundation and the (Canadian) Natural Science and Engineering Research Council.
M. R. Flynn, A. R. Kasimov, J.-C. Nave, R. R. Rosales, and B. Seibold. Self-sustained nonlinear waves in traffic flow. Physical Review E, 2009; 79 (5): 056113 DOI
(source : sciencedaily)
The Research Group in Mathematical Programming, Logistics and Simulation (PROMALS) and the Seat Chair of Innovation and Sustainable Development (Seat-UPC) create technological solutions to improve traffic flow, make driving safer and more comfortable, lower the accident rate and reduce traffic congestion and emissions of contaminant gases.
New advances will see vehicles equipped with sensors and interfaces which gather information on the traffic situation and display it on screen or alert the driver through automated voice announcements. The Seat-UPC Chair is involved in designing and fitting human machine interfaces (HMIs) and running automated tests of the electronic systems used in the MARTA project, which incorporate new technologies such as specialized image recognition applications.
New on-board sensors will be able to monitor the status of mechanical components such as brakes when a vehicle is in motion, while others will provide automatic control of driving speed and the distance maintained from the vehicle in front. Interfaces will enable data to be shared between vehicles, providing updated information on their position and speed every 200 meters. A system of nodes installed in the road network transmits the data to a mobility management center, where they are processed and used to maintain traffic flow by providing real-time information on congestion spots and suggesting optimum routes in the event of an accident.
The PROMALS group, attached to the Department of Statistics and Operations Research at the UPC, is looking at ways of using the data received by the management center. Its researchers are designing simulated traffic scenarios in which to test the new technologies developed under the MARTA project: a recent example is a traffic priority system in which the real-time data are used to determine the ideal intervals between traffic light phases across a given area, which optimizes traffic flow and reduces congestion.
The MARTA project has a budget of over thirty-five million euros and receives funding from the Center for the Development of Industrial Technology (CDTI). The project, scheduled for completion in 2011, is coordinated by the company FICOSA as part of a wider program run by the National Strategic Consortium in Technical Research (CENIT), and brings together experts and researchers from nineteen companies and nineteen scientific centers and national universities.
Source : sciencedaily