相河 聡

前十字靭帯(ACL;Anterior cruciate ligament)の損傷により出現した膝関節の不安定性はスポーツ成績に悪影響を与えるため，ACLを再建し安定した膝を作ることが必要である．ACL再建術の術後成績はACL挿入のための骨孔の位置と角度に強い相関があることが知られているため，骨孔開口の最適化は術後成績向上の重要な因子である．しかし，現在の術式では医師が内視鏡下で骨孔位置と角度を決定しているため，血管や靭帯を傷つける可能性があり，これがACL再建術の正確性や再現性を低下させていると考えられる．ACL再建術の術後評価法として単純X線画像を用いて骨孔位置，角度を評価するQuadrant法がある．本研究では，MR画像を用いた骨孔の位置と角度の評価を行う計算機診断支援システムを提案する．提案手法ではMR画像を用いたQuadrant法により，大腿顆周辺の血管や靭帯の3次元位置を考慮した骨孔位置を決定する．本システムをACL損傷患者に適用した結果，正確性と再現性の向上が確認できた．

A continuous-switching type array antenna receiver has been proposed in order to reduce the deterioration due to fast-fading channel variations and improve communication performance. The receive antennas are placed in a linear array, and by sequentially switching the elements in the opposite direction to the direction of the train travel, it has been possible to fix the signal receiving point virtually. Through the development of a scale-model experiment of high-speed movement using the prototype antenna, in this paper we show that it is possible through optimized antenna element selection and appropriate signal processing to reduce the fading rate and improve the performance of an OFDM system. A software simulation based on the Worldwide Interoperability for Microwave Access (WiMAX) physical layer parameters was made and data transmitted at RF in a 5 MHz bandwidth with symbol rate appropriately scaled to simulate a range of fading speeds. The receive antenna array consisting of eight elements traverses a track at a virtual speed of 180 km/h and the error rate performances with and without switching are compared.

Immune cells deeply affect human health, however, it has not been investigated well due to difficulty of observing immune cells in vivo. The recent study enables us to acquire single Macrophage, which is the representative cell of immune cells, in vivo using 11.7 T magnetic resonance imaging (MRI). To quantify the kinematics of macrophages, it requires detection and tracking macrophages in MR image. The kinematic analysis will help researchers to investigate the mechanism of autoimmune diseases. This paper proposes an automated single macrophage tracking method in mouse brain 11.7 T time-lapse MR images. The method detects macrophages using background subtraction algorithm, and tracks macrophages using the Hungarian algorithm. The results showed that the proposed method detected and tracked macrophages in MR images successfully.

Anterior cruciate ligament (ACL) injury causes knee joint instability, and effects on sports performance. Therefore, ACL reconstruction is essential to keep their high performance. It is well known that the outcome of ACL reconstruction is strongly related to the placement and orientation of the bone tunnel. Therefore, optimization of tunnel drilling technique is an important factor to obtain satisfactory surgical results. Current procedure relies on arthroscopic evaluation and there is a risk of damaging arteries and ligaments during surgery. The damages may reduce the accuracy and reproducibility of ACL reconstruction. As a postoperative evaluation method, a quadrant method has been used to evaluate the placement and orientation of the bone tunnel in X-ray radiography. This study proposes a computer-aided surgical planning system for evaluating ACL insertion site and orientation using magnetic resonance (MR) images. We first introduce MR image based the quadrant method to determine the ACL insertion site for preoperative patients. It also evaluates the 3-D spatial relationship between the planning femoral drilling hole and arteries around the femoral condyle. This system has been applied to ACL injured patients, it may increase the accuracy and reproducibility of ACL bone tunnel, and it can evaluate a risk of damaging the surrounding arteries and ligaments. (C) 2015 The Authors. Published by Elsevier B.V.

The neonatal cerebral disorders severly languish the quality of life (QOL) of patients and also their families. It is required to detect and cure in their early stage for the sake of decreasing the degree of symptoms. However, it is difficult to evaluate neonatal brain disorders based on morphological analysis because the neonatal brain grows quickly and the brain development progress is different from person to person. Previously, we proposed a method of calculating growth index using Manifold learning. The growth index is effective to evaluate the brain morphological development progress, although, it does not directly correspond to the brain development delay. To evaluate brain development delay, this paper proposes an estimation method of neonatal brain age using Manifold learning, principal component analysis, and multiple regression model. The regression model is trained using a 4-D standard brain, which is constructed using training subjects with growth index. To evaluate the proposed method, we constructed a multiple regression model using 11 normal subjects (revised age: 0-4 month old), and estimated brain age of 4 normal subjects. And, we estimated brain age of 4 abnormal subjects to evaluate the detection accuracy of brain development abnormality. The results showed that the method found the differences of brain development for abnormal subjects.

The neonatal cerebral disorders severly languish the quality of life (QOL) of patients and also their families. It is required to detect and cure in their early stage for the sake of decreasing the degree of symptoms. However, it is difficult to evaluate neonatal brain disorders based on morphological analysis because the neonatal brain grows quickly and the brain development progress is different from person to person. Previously, we proposed a method of calculating growth index using Manifold learning. The growth index is effective to evaluate the brain morphological development progress, although, it does not directly correspond to the brain development delay. To evaluate brain development delay, this paper proposes an estimation method of neonatal brain age using Manifold learning, principal component analysis, and multiple regression model. The regression model is trained using a 4-D standard brain, which is constructed using training subjects with growth index. To evaluate the proposed method, we constructed a multiple regression model using 11 normal subjects (revised age: 0-4 month old), and estimated brain age of 4 normal subjects. And, we estimated brain age of 4 abnormal subjects to evaluate the detection accuracy of brain development abnormality. The results showed that the method found the differences of brain development for abnormal subjects.

A sequentially switched antenna array receiver (SSAAR) has been developed in order to lessen the fast-fading effects on super-express trains. The array elements are switched in reverse sequence to the direction of the train motion. To demonstrate the performance improvements, measurements were made using a scale model train with receiver moving at 3.6 km/h. A software simulation based on the Worldwide Interoperability for Microwave Access (WiMAX) physical layer parameters was developed and by proportionally reducing the transmission symbol rate, performances for virtual speeds of up to 360 km/h have been measured. The paper shows that the performance could be improved by up to 1.7 dB at bit error rate (BER) 5E-3 whilst traveling at virtual speed of 360 km/h.

A continuous-switching type array antenna receiver has been proposed in order to reduce the deterioration due to fast-fading channel variations and improve communication performance. The receive antennas are placed in a linear array, and by sequentially switching the elements in the opposite direction to the direction of the train travel, it has been possible to fix the signal receiving point virtually. Through the development of a scale-model experiment of high-speed movement using the prototype antenna, in this paper we show that it is possible through optimized antenna element selection and appropriate signal processing to reduce the fading rate and improve the performance of an OFDM system. A software simulation based on the Worldwide Interoperability for Microwave Access (WiMAX) physical layer parameters was made and data transmitted at RF in a 5 MHz bandwidth with symbol rate appropriately scaled to simulate a range of fading speeds. The receive antenna array consisting of eight elements traverses a track at a virtual speed of 180 km/h and the error rate performances with and without switching are compared.

Immune cells deeply affect human health, however, it has not been investigated well due to difficulty of observing immune cells in vivo. The recent study enables us to acquire single Macrophage, which is the representative cell of immune cells, in vivo using 11.7 T magnetic resonance imaging (MRI). To quantify the kinematics of macrophages, it requires detection and tracking macrophages in MR image. The kinematic analysis will help researchers to investigate the mechanism of autoimmune diseases. This paper proposes an automated single macrophage tracking method in mouse brain 11.7 T time-lapse MR images. The method detects macrophages using background subtraction algorithm, and tracks macrophages using the Hungarian algorithm. The results showed that the proposed method detected and tracked macrophages in MR images successfully.

The traffic from many smartphones in a bullet train is increasing and there is a fear of the capacity lack in the train-unit entrance circuit. In the Sequentially Switched Antenna Array Receiver, the array antenna elements fix the receiving point against the travel of the bullet train. In addition, it is necessary to synchronize the switching with the sampling period. We propose a multiple antenna combining scheme that satisfies the requirements fir the sequentially switching, and show its effectiveness by computer simulations using experimental data.

情報化社会の発展に伴いスマートフォンやタブレット端末が一般的になりつつある．現在では Wi-Fi スポットなどの整備が進み，無線 LAN が身近な通信手段のひとつとなっている．これら無線 LAN アクセスポイントの受信信号強度 （RSSI:Received Signal Strength lndicator） を利用した位置推定技術が検討されている．無線 LAN を用いた位置推定法の中に事前にデータベースを構築する Scene Analysis 方式がある．しかし測定する段階での一時的な環境変動によりデータベースに不具合が生じると推定精度が低下する．そこで，作成したデータベースから近似式を求め，それをもとに校正を行う手法を提案し実験的評価を行う．Smart phones and tablets are gaining popularity with development of an information-oriented society. Since the Wi-Fi spot spread, wireless LAN is one of the familiar means of communications. As one of the position estimate technology using wireless LAN, the method of using RSSI (Received Signal Strength Indicator) is examined. The method of building a database in advance (Scene Analysis method) is one of the position estimate methods using wireless LAN. However, if fault arises in a database by a fluctuation, accuracy will fall. Then, it asks for an approximate expression from the created database, the technique of proofreading based on it is proposed, and empirical assessment is performed.

近年，無線LANは身近な通信手段の一つとして普及している．これに伴い，受信電界強度 (RSSI：Received Signal Strength Indicator) を利用した位置推定が低コストで有用な手段として検討されている．しかし，RSSI はマルチパスなどの影響により変動するため，マルチパスフェージングは位置推定精度悪化の大きな要因となる．そこで，我々は無線 LAN 端末に複数の素子を設置する空間受信ダイバーシチ技術に着目し，位置推定に利用する手法を提案する．本稿では RSSI 位置推定法で一般的な Lateration 方式及び SceneAnaIysis 方式を用いて提案手法の実験的評価を行う．Localization system using RSSI of wireless-LAN is under consideration as a low-cost and useful method. However, RSSI will vary due to the effects of multi-path. So multi-path fading is a major factor of Localization accuracy deterioration. Therefore, we propose the technique of using it for Localization paying attention to the space receiving diversity technology of installing multiple receiving elements in a wireless LAN terminal. In this paper, we perform empirical assessment of the proposed method using Scene Analysis method and Lateration method which are a common among the Localization method using the RSSI.

近年,無線LANは身近な通信手段のひとつとして普及している.これに伴い,受信電界強度(RSSI:ReceivedSignalStrengthIndicator)による位置推定技術が低コストで有用な手段として検討されている.無線LANを用いた位置推定法ではマルチパスや使用環境による電波伝搬が場所により異なり一様に減衰しない.そこで,RSSIデータベースを参照して位置推定を行うSceneAnalysis方式が高精度であり,距離と減衰量の関係が一様でない環境下では適している.しかし,データベースの構築がには予めRSSIを測定する必要がある.そこで,自己位置推定する度に減衰定数を学習しデータベースを構築する手法を提案し実験的評価を行う.

近年，無線 ＬＡＮ は身近な通信手段のひとつとして普及している．これに伴い，受信電界強度 （RSSI：Received Signal Strength Indicator） による位置推定技術が低コストで有用な手段として検討されている．無線 LAN を用いた位置推定法ではマルチパスや使用環境による電波伝搬が場所により異なり一様に減衰しない．そこで， RSSI データベースを参照して位置推定を行う Scene Analysis 方式が高精度であり，距離と減衰量の関係が一様でない環境下では適している．しかし，データベースの構築がには予め RSSI を測定する必要がある．そこで，自己位置推定する度に減衰定数を学習しデータベースを構築する手法を提案し実験的評価を行う．Localization system using RSSI of wireless-LAN is under consideration as a low-cost and useful method. This localization system is affected according to multipass in indoor environment. Thus, Scene-Analysis Method using RSSI database gets high accuracy under the environment of electric wave change. However, making database needs a big labor. In this study suggest the database construction Method that learns a decay constant and experiment the method.

2.4GHz帯に代表されるISM帯では無線LANやBluetoothなど,複数の無線通信システムが自律分散的に運用されている.このため,非協調的に設定された各々の運用周波数や,システム間干渉の発生により,既存システムの利用が困難な未使用周波数資源が散在するという問題が生じる.そこで,筆者らはこの問題を解決することで,ISM帯における効率的な周波数利用や複数システム間周波数共用を実現する,ダイナミックスペクトラムアクセスを用いた無線通信システムの研究開発を実施している.本稿では本研究開発の内容,および得られた成果を概説する.

In a hospital, many equipments use electro-magnetic wave. The equipment which uses for energy transmits very high power. This high power electro-magnetic wave disturbs other electronic equipments which use the same frequency. To avoid the disturbance, frequency selective shielding technologies are effective. The laminated structure consisting of metal wire grid and dielectric layer are studied. The characteristics of these structures are controlled by the parameters such as wire diameter and spacing. The characteristics are calculated by the use of the transmission line model, and measured. All the measured results show good match with the calculated results.

自律移動ロボットが位置推定に無線 LAN の受信レベルを用いる場合，周辺環境により各位置での推定精度が異なる．一方，移動ロボットは複数箇所で位置推定を行うことができる．このことから，各点での位置推定結果に移動履歴を加えて得られる現在位置を複数平均する到達精度向上手法を提案する．具体的には，位置推定履歴と移動履歴から複数の推定現在地を算出し平均することで特異点を平坦化させる．さらに提案法を搭載した自律移動ロボットを用いた実験により有効性の検証を行った．In the case that autonomous mobile robot uses wi-fi for localization, localization accuracy depends on the position by surrounding environment. On the other hand, mobile robot can estimate its location on more than one place. And so we propose localization-method using average of a few localization and movement records to improve arrival accuracy. In particular we get a localization from averaged-localization which are worked out from localization and movement records and it is flattered difference. In addition, we surveyed effectiveness of the method by having experiment with autonomous mobile robot which has the method.