BACKGROUND To improve our understanding of the neighborhood environment - physical activity (PA) relationship, it is of importance to assess associations between neighborhood environmental characteristics and neighborhood-based PA. METHODS Participants' (N = 308; 45-65 years) light PA (LPA) and moderate-vigorous PA (MVPA) within a 400, 800, and 1600 m buffer around adults' homes was measured ...

Nodes in Mobile Opportunistic Network (MON) have to cache packets to deal with the intermittent connection. The buffer management strategy obviously impacts the performance of MON, and it attracts more attention recently. Due to the limited storage capacity of nodes, traditional buffer management strategies just drop messages based on the property of message, and they neglect the collaboration ...

Storage management is an important part of DB2. The buffer pool in DB2 is used to catch the disk pages of the database, and its management algorithm can significantly affect performance. Because of the complexity of DB2 and the workloads running on it, the buffer pool management algorithm is hard to study, config, and tune. In order to investigate the buffer pool management algorithm under cont...

Most embedded database systems are built on a two-level memory hierarchy, a RAM buffer on top of flash memory. Both kinds of memories have limited capacity, thus, how to efficiently utilize them is critical for embedded systems with resource restrictions. Different from magnetic hard disk, flash memory has speed asymmetry in reads and writes, i.e., random reads are over an order of magnitude fa...

Delay Tolerant Network (DTN) routing protocols works in an environment where there is no guarantee of end to end path between source and destination. DTNs operate with the principle of store, carry and forward. Mobile nodes have limited buffer space and contact opportunity. So the resources are useful and must be used optimally. The routing protocol message replication strategies react differen...

Acquiring content through mobile networks is a basic and general topic. Mobile nodes have two different ways of obtaining data. The first method is to download data quickly through 3G/4G networks, which is expensive. The second way is to get data from other nodes by means of delay tolerant networks (DTN), which are much cheaper, but are time-consuming. Throwboxes deployed in DTN act as fixed fe...