Abstract: Provided are a method and apparatus for partially encrypting speech packets, more specifically, a method and apparatus for selecting partial encryption sets used for a partial encryption technique in which compressed speech packets are partially encrypted to obtain the same effect as a full encryption technique. The method includes the steps of: (a) compressing respective speech files stored in a large-capacity speech database into the speech packets using a speech codec; (b) measuring single-bit loss distortion and sequential-bit loss distortion of the speech packets compressed in step (a); (c) generating standards for selecting partial encryption sets based on the measurement results of the single-bit loss distortion and sequential-bit loss distortion; (d) selecting the partial encryption sets according to the generated standards; and (e) encrypting the speech packets using the selected partial encryption sets.

Abstract: An encrypted backup data storage device and a storage system using the same are provided. A backup memory stores at least one of plain-text data and a secret key. A leakage current blocking circuit includes at least one inverter and a complementary metal oxide semiconductor (CMOS) NAND gate circuit and cuts off leakage current paths formed by the lines connected to the battery backup memory.

Abstract: Provided are a method and apparatus for partially encrypting speech packets, more specifically, a method and apparatus for selecting partial encryption sets used for a partial encryption technique in which compressed speech packets are partially encrypted to obtain the same effect as a full encryption technique. The method includes the steps of: (a) compressing respective speech files stored in a large-capacity speech database into the speech packets using a speech codec; (b) measuring single-bit loss distortion and sequential-bit loss distortion of the speech packets compressed in step (a); (c) generating standards for selecting partial encryption sets based on the measurement results of the single-bit loss distortion and sequential-bit loss distortion; (d) selecting the partial encryption sets according to the generated standards; and (e) encrypting the speech packets using the selected partial encryption sets.

Abstract: A method for recovering a frame erasure at a voice over internet protocol (VoIP) environment is provided. The method includes: extracting coder parameters of received packets; if an erased packet exists during the extracting of the coder parameters, regenerating speech characteristic parameters of the erased packet by referencing a vector quantization codebook index interpolation table (VCIIT) formulated based on representative values of speech characteristic parameters reflecting auditory recognition characteristics and performing a linear interpolation on speech characteristic parameters of the normally received packets allocated previous and future of the erased packet; and recovering the erased packet by combining the regenerated speech characteristic parameters. The proposed frame erasure recovery method can minimize an additional delay and increases in bandwidth and computation and improve a capability of recovering the erasure.

Abstract: The present invention is about a method for assigning channels in a mobile communication system, having the function to analyze the marginal resources according to each operation mode and thereby to maximize the efficiency of a multi-channel DSP. The present invention includes the steps of: a) checking what an input call is among the three modes of vocoding, bypass and data service; b) deciding whether there is a usable channel for the same mode as the input call requires; c) if there is a usable channel for the same mode as the input call requires, assigning the input call to a dedicated channel for the same mode as the input call requires; and d) if there is no usable channel for the same mode as the input call requires, assigning the input call to a complex channel in case that there is a usable complex channel.

Abstract: The present invention is about a method for assigning channels in a mobile communication system, having the function to analyze the marginal resources according to each operation mode and thereby to maximize the efficiency of a multi-channel DSP. The present invention includes the steps of: a) checking what an input call is among the three modes of vocoding, bypass and data service; b) deciding whether there is a usable channel for the same mode as the input call requires; c) if there is a usable channel for the same mode as the input call requires, assigning the input call to a dedicated channel for the same mode as the input call requires; and d) if there is no usable channel for the same mode as the input call requires, assigning the input call to a complex channel in case that there is a usable complex channel.