LAN通信システムの一中継局を含むポイント・トゥ・ポイント平均応用時間の近似解析

上位プロトコル処理時間が無視できないような高速LANの通信システムを対象とした一中継局を含むポイント・トウ・ポイント平均応答時間の性能評価を行った.ユーザトランザクションが通信システムを往復通過する時間を応答時間と定義している.階層型通信システムの各階層モジュールの平均処理時間と制御メッセージ数から，一中継局を含むポイント・トウ・ポイントの平均応答時間を近似的に求めいる.実測平均応答時間の上限値と下限値との比較より，過負荷を除くトラヒック範囲で，本解析手法は有効であることを示した.情報処理研究報告 Vol.90 No.1

Study on the Throughput Limits over the HDLC Protocol

This paper describes the throughput evaluation of the high level data link control protocol. The analytical models are outlined and the throughput analysis is carried out under fully loaded condition for the following three error recovery schemes: (1)Checkpoint retransmission scheme, (2)SREJ recovery scheme and (3)REJ recovery scheme. We derive the optimal packet text length which achieves the maximum throughput for each error recovery scheme. Also we denote the optimal window size for the checkpoint retransmission scheme

Application of Punctured Turbo Codes with Unequal Error Protection to Wireless ATM Networks

In the wireless asynchronous transfer mode (ATM) networks, a custom data link control (DLC) layer protocol with stronger error correction ability is needed for mitigating the affect of radio channel errors. This paper applies punctured turbo code schemes to the protection of the header and various payloads in wireless ATM cell, which are realized by the combination of programmable interleaving and puncturing. Their performance is analyzed for Rayleigh fading channel, which shows more significant reduction in cell loss rate (CLR) than the previous systems. Our proposal also provides good balance designs for CLR and the payload bit error rate (BER), and offers potential for future evolutionary improvement of the wireless ATM codingscheme

後腹膜出血にて発症した腎血管筋脂肪種

47歳男, 左側腹部痛を主訴に入院した.画像診断上, 腎血管筋脂肪腫とその破裂による後腹膜血腫がもっとも疑われ, 迅速診断の上, 血腫除去と摘出術が行われたWe report a case of renal angiomyolipoma with retroperitoneal hemorrhage treated by enucleation in a 47 year-old male. The mass in the anterior side of the left kidney, revealed by sonography and CT, was diagnosed as angiomyolipoma with a retroperitoneal hematoma caused by its spontaneous rupture. Removal of hematoma and enucleation of the tumor were performed after the diagnosis. Diagnosis and treatment of ruptured renal angiomyolipoma are discussed