Abstract: Provided are a biodegradable aliphatic-aromatic polyester copolymer having excellent hydrolysis resistance and high viscosity which has a carboxyl end group (CEG) content of 15 mg KOH/g or less, a ratio (Mz/Mn) of a z-average molecular weight (Mz) to a number average molecular weight (Mn) of 3 to 15, and a melt index (MI) of 5 g/10 min or less as measured under conditions of a temperature of 190° C. and a load of 2.16 kg in accordance with ASTM D 1238. A method of preparing a biodegradable aliphatic-aromatic polyester copolymer is provided, including adding a chain extender and an anti-hydrolysis agent to an aliphatic-aromatic polyester pre-copolymer over time, whereby a significant viscosity rise and improvement of hydrolysis resistance may be implemented simultaneously.

Abstract: Provided are a biodegradable aliphatic-aromatic polyester copolymer having excellent hydrolysis resistance and high viscosity which has a carboxyl end group (CEG) content of 15 mg KOH/g or less, a ratio (Mz/Mn) of a z-average molecular weight (Mz) to a number average molecular weight (Mn) of 3 to 15, and a melt index (MI) of 5 g/10 min or less as measured under conditions of a temperature of 190° C. and a load of 2.16 kg in accordance with ASTM D 1238. A method of preparing a biodegradable aliphatic-aromatic polyester copolymer is provided, including adding a chain extender and an anti-hydrolysis agent to an aliphatic-aromatic polyester pre-copolymer over time, whereby a significant viscosity rise and improvement of hydrolysis resistance may be implemented simultaneously.

Abstract: An audio codec system and an encoding method using the same are provided. According to the method, encoding and decoding processes are repeatedly performed so as to determine optimized coding parameters when analog audio signals being inputted are encoded. The processes of encoding and decoding inputted analog audio signals using initial coding parameters, and computing new parameters using a differential computed during the encoding process are repeatedly performed.

Abstract: Apparatus and method for reproducing a MIDI-based music file are provided. According to the apparatus and method, a plurality of notes and note reproduction times are extracted from the MIDI file, a section where envelope values of sound source samples exponentially reduce is changed into a linear section, and the sound source samples are outputted according to the note reproduction times by reflecting the slope of the linear section.

Abstract: There is provided a method of synthesizing a musical instrument digital interface (MIDI) having wave table support. The wave table sample information is modified based on the newly searched loop segment, the interval of the newly searched loop segment, and the fine tune data. Therefore, the size of the wave table can be reduced.

Abstract: Provided are an apparatus and a method for processing a ringtone in a wireless terminal. Position data of sound source samples corresponding to ringtone contents are extracted in advance and then used to play the ringtone. Musical score data are parsed from ringtone contents, and position data of the sound source samples corresponding to the parsed musical score data are extracted and stored in a database. Instead of parsing the sound source samples each time, by storing the position data of the sound source samples corresponding to the musical score data in a database, system load can be reduced during a real time playback of a ringtone.

Abstract: Provided are an apparatus and a method for processing MIDI in a wireless terminal capable of controlling a volume of sound source samples when the MIDI is played. According to the method, a plurality of notes, volume levels, volume section information, and note playback duration information are extracted from an inputted MIDI file. After a volume sample number in each section is calculated using the extracted volume level and the volume section information, a volume of the sound source samples that correspond to a note that is to be played is controlled using the volume sample numbers. Next, frequency of the sound source samples are converted to a frequency assigned to the notes and the sound source samples are outputted, reducing a system load caused by the real-time play of the MIDI.

Abstract: An apparatus and a method for synthesizing a MIDI based on a wave table are provided. According to the method, sound samples of a plurality of instruments stored in a wave table are compressed and stored so as to reduce the storage space required by the wave table. Bit streams for the samples are decoded to synthesize a MIDI when a specific instrument's sound samples are requested.

Abstract: Provided is a frame synchronization pattern design and synchronization method by which in a transmitter of a communications system employing an orthogonal frequency division multiplexing (OFDM), a frame synchronization pattern is inserted into the starting part of a symbol frame, and by detecting the frame synchronization pattern in a receiver, synchronization of the OFDM transmitter and receiver is performed. Also, provided are a transmitter synchronization apparatus including an OFDM symbol frame generation unit, a frame synchronization pattern insertion unit, and an OFDM transmission signal conversion unit, and a receiver synchronization apparatus comprising a frame synchronization pattern inserted OFDM symbol frame conversion unit, a frame synchronization pattern detection unit, and a source data generation unit.