Abstract: Disclosed are a device and method for preparing fatty acid derivatives and more specifically, a device for preparing fatty acid derivatives including three reactors and a method for effectively preparing fatty acid derivatives. The device for preparing fatty acid derivatives including three reactors enables a stable supply of reactants even if a problem occurs in one reactor, and enables continuous and stable operation because delays in the treatment and purification process do not occur. As a result, the device has effects of increasing productivity and reducing production costs. In other words, by operating three reactors instead of two reactors, it is possible to build a production facility that can be operated continuously without stopping, resulting in increased production and reduced production costs. The reactors are operated at a time interval so that only one ammonia feeder and one ammonia collector may be used for all three reactors.

Abstract: An apparatus and method for managing a packet transmission delay for TCP/IP-based communications in a mobile communication system are provided, in which a BSC imposes no delay on a packet directed to an MS or a packet transmitted from the MS and sends the packet to the MS or corresponding MS, if it is determined that the MS starts to perform a handover during communications with the MS, and delays a packet directed to the MS or a packet transmitted from the MS and sends the delayed packet to the MS or corresponding MS, if it is determined that the MS has completed the handover during the packet transmission with no delay. Advantageously, timeout occurrences caused by too long a time delay are reduced, thereby preventing decreased throughput during the TCP/IP-based handover.

Abstract: An apparatus and method for managing a packet transmission delay for TCP/IP-based communications in a mobile communication system are provided, in which a BSC imposes no delay on a packet directed to an MS or a packet transmitted from the MS and sends the packet to the MS or corresponding MS, if it is determined that the MS starts to perform a handover during communications with the MS, and delays a packet directed to the MS or a packet transmitted from the MS and sends the delayed packet to the MS or corresponding MS, if it is determined that the MS has completed the handover during the packet transmission with no delay. Advantageously, timeout occurrences caused by too long a time delay are reduced, thereby preventing decreased throughput during the TCP/IP-based handover.

Abstract: Disclosed is an accounting system and method based on network service quality in a mobile communication system. The system and method for controlling accounting according to quality of service (QoS) information of a packet data service system, comprises allocating by a packet data service node QoS based on QoS profiles transmitted from an authentication, authorization, and accounting (AAA) server and setting by the packet data service node a service instance which is able to differentiate applications according to QoS levels, the packet data service node having received the QoS information requested to be set from a mobile station, and after service is started, adding by the packet data service node the allocated QoS information to accounting information including information regarding an amount of packet data transmitted to the mobile station so as to transmit the allocated QoS information to the AAA server.

Abstract: A system and method of providing a Push-To-Talk (PTT) service in a mobile communication system are provided. Particularly, a new service option for the PTT service is defined and set before a call setup between a mobile station (MS) and a base station (BS) in order to allow the MS and the BS to recognize a PTT call. Upon receipt of an origination message including the service option of the PTT service from the MS, the BS establishes a Radio Link Protocol (RLP) with the MS and establishes a Point-to-Point Protocol (PPP) session to provide the PTT service in packet data to the MS.