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Existing mobile platforms are based on manual way of granting and revoking permissions to applications. Once the user grants a given permission to an application, the application can use it without limit, unless the user manually revokes the permission. This has become the reason for many privacy problems because of the fact that a permission that is harmless at some occasion may be very dangerous at another condition. One of the promising solutions for this problem is context-aware access control at permission level that allows dynamic granting and denying of permissions based on some predefined context. However, dealing with policy configuration at permission level becomes very complex for the user as the number of policies to configure will become very large. For instance, if there are A applications, P permissions, and C contexts, the user may have to deal with A × P × C number of policy configurations. Therefore, we propose a context-aware role-based access control model that can provide dynamic permission granting and revoking while keeping the number of policies as small as possible. Although our model can be used for all mobile platforms, we use Android platform to demonstrate our system. In our model, Android applications are assigned roles where roles contain a set of permissions and contexts are associated with permissions. Permissions are activated and deactivated for the containing role based on the associated contexts. Our approach is unique in that our system associates contexts with permissions as opposed to existing similar works that associate contexts with roles. As a proof of concept, we have developed a prototype application called context-aware Android role-based access control. We have also performed various tests using our application, and the result shows that our model is working as desired. Copyright © 2017 John Wiley & Sons, Ltd.

We are developing a compact and high-sensitivity brain-dedicated PET scanner, which consists of a hemispherically arranged detector unit and an add-on detector unit. Following our first idea of using a chin position as the location of the add-on detector (helmet-chin PET), a neck position has been selected as the location (helmet-neck PET). We have developed prototypes of both geometries using the 4-layered depth-ofinteraction (DOI) detector (2.8 mm sized GSOZ scintillators and a 64 ch PMT) which does not have time-of-flight (TOF) capability. On the other hand, a new TOF-PET detector module which consists of 4.1 mm sized LFS scintillators and multi pixel photon counters (MPPCs) is now commercially available (C135004075LC-12, Hamamatsu Photonics K.K.). Using one-to-one crystal-photodetector coupling, it is possible to achieve a 280 ps coincidence resolving time (CRT), although the Anger-type calculation, which is essential for the 4-layered DOI detector, cannot be applied. In this paper, therefore, we investigated the suitability of this TOF-PET detector module for the next helmetneck PET. At first, the helmet-neck PET with 20 mm crystal length, which is a standard parameter of the module, was modeled by GEANT4, and performance results were compared with those of the current helmet-neck PET prototype. We observed a compromised image quality; the non-DOI capability counteracted the TOF gain. On the other hand, the helmet-neck PET with shortened crystal length (10 mm) outperformed the current helmet-neck PET prototype; the shortened crystal length reduced the parallax error, and TOF information compensated for the loss of sensitivity. Based on the GEANT4 simulation results, we fabricated a one-pair prototype of the TOF-PET module with 10 mm length, which yielded 11.6 % energy resolution at 511 keV and 281.8\pm 9.6 ps CRT at FWHM. In conclusion, we confirmed suitability of the 280 ps-CRT non-DOI detector for the next helmet-neck PET.

Prediction of airline ticket prices and or demand is very challenging as it depends on various internal and external factors that can dynamically vary within short period of time. Researchers have proposed different types of ticket price/demand prediction models with the aim of either assisting the customer forecast ticket prices or aid the airline to predict the demand. In this paper, we present a review of customer side and airlines side prediction models. Our review analysis shows that models on both sides rely on limited set of features such as historical ticket price data, ticket purchase date and departure date. A combination of external factors such as social media data and search engine query in conjunction with advanced machine learning techniques are not considered.

The energy internet is a new emerging concept which is mainly associated with peer to peer energy trading in a smart grid power network. To facilitate this, support for bidirectional power flow in addition to a bidirectional communication flow is needed. Thus energy routing functions/algorithms and energy routing devices are the core entities constituting the energy internet. In this paper we are mainly concerned with energy routing algorithms. These energy routing algorithms are designed based on various techniques such as graph theory, game theory and autonomous systems. Given the infancy of this area of research, in this paper, we review the state of the art of energy routing algorithms. We first introduce the concept of energy routing and then, we present a comprehensive literature survey of existing energy routing algorithms. Furthermore, we provide a discussion of our findings and future directions.

Due to the expansion of distributed renewable energy resources, peer to peer energy trading (P2P DET) is expected to be one of the key elements of next generation power systems. P2P DET can provide various benefits such as creating a competitive energy market, reducing power outages, increasing overall efficiency of power systems and supplementing alternative sources of energy according to user preferences. Because of these promising advantages, P2P DET has attracted the attention of several researchers. Current research related to P2P DET include demand response optimization, power routing, network communication, security and privacy. This paper presents a review of the main research topics revolving around P2P DET. Particularly, we present a comprehensive survey of existing demand response optimization models, power routing devices and power routing algorithms. We also identify some key challenges faced in realizing P2P DET. Furthermore, we discuss state of the art enabling technologies such as Energy Internet, Blockchain and Software Defined Networking (SDN) and we provide insights into future research directions.

Due to the expansion of small scale distributed energy resources such as solar rooftop and PEVs, decentralized energy trading is expected to be one of the most important components of next generation power systems. Decentralized peer-to-peer energy exchange systems are believed to be a promising solution not only to solve the scalability and mobility problems in the existing system but also to create a competitive market that can benefit small scale prosumers and consumers. However, such systems need to be equipped with the necessary security, privacy and payment transaction mechanisms to be efficient and trusted. In this paper, we propose a decentralized energy exchange system based on Blockchains. Blockchains is a technology that supports secure transactions between participating entities in a decentralized peer-to-peer network. The proposed system allows for energy exchange between prosumers using a form of smart electronic contracts which are based on Blockchains.

Charging of plug-in electric vehicles (PEVs) exposes smart grid systems and their users to different kinds of security and privacy attacks. Hence, a secure charging protocol is required for PEV charging. Existing PEV charging protocols are usually based on insufficiently represented and simplified charging models that do not consider the user’s charging modes (charging at a private location, charging as a guest user, roaming within one’s own supplier network or roaming within other suppliers’ networks). However, the requirement for charging protocols depends greatly on the user’s charging mode. Consequently, available solutions do not provide complete protocol specifications. Moreover, existing protocols do not support anonymous user authentication and payment simultaneously. In this paper, we propose a comprehensive end-to-end charging protocol that addresses the security and privacy issues in PEV charging. The proposed protocol uses nested signatures to protect users’ privacy from external suppliers, their own suppliers and third parties. Our approach supports anonymous user authentication, anonymous payment, as well as anonymous message exchange between suppliers within a hierarchical smart grid architecture. We have verified our protocol using the AVISPA software verification tool and the results showed that our protocol is secure and works as desired.

Users of plug-in-electric vehicles (PEV) often need to charge outside their home power grid networks i.e. outside their supplier. This basically constitutes a roaming charging case. Hence, users should be protected from possible security and privacy attacks. Moreover, remote authorization and payment transaction mechanism is required between the different power suppliers. In this paper, we propose a secure charging and payment transaction protocol for roaming PEV charging. Our protocol is developed based on the principles of the Secure Electronic Transaction (SET) protocol. The protocol protects user's privacy not only from external suppliers but also from their own suppliers. Moreover, our protocol is designed in such a way that it is robust against the known security attacks. Our proposed work provides anonymous authorization and payment simultaneously not only between the roaming user and an external supplier but also between suppliers.

The purpose of this work is to build a validated simulation model of a whole-body PET scanner constructed from the four-layer depth-ofinteraction detectors developed at the National Institute of Radiological Sciences, Japan, using the Geant4 Monte Carlo toolkit. Once validated, the model can then be used to generate an expected PET image from the treatment plan for comparison to the image acquired during treatment, which will assist in the development of methods for directly estimating the delivered dose from the measured positron-annihilation map.

Complications of an unsafe abortion are a major contributor to maternal deaths and morbidity in Africa. When abortions are performed in safe environments, such complications are almost all preventable. This paper reports results from a nationally representative health facility study conducted in Ethiopia in 2008. The safe abortion care (SAC) model, a monitoring approach to assess the amount, distribution, use and quality of abortion services, provided a framework. Data collection included key informant interviews with 335 health care providers, prospective data on 8911 women seeking treatment for abortion complications or induced abortion and review of facility logbooks. Although the existing hospitals perform most basic abortion care functions, the number of facilities providing basic and comprehensive abortion care for the population size fell far short of the recommended levels. Almost one-half (48%) of women treated for obstetric complications in the facilities had abortion complications. The use of appropriate abortion technologies in the first trimester and the provision of post-abortion contraception overall were reasonably strong, especially in private sector facilities. Following abortion law reform in 2005 and subsequent service expansion and improvements, Ethiopia remains committed to reducing complications from an unsafe abortion. This study provides the first national snapshot to measure changes in a dynamic abortion care environment.

Objectives: With progress in clinical studies on recently developed diagnostic medicine approaches for dementia, there is an emerging demand for dedicated brain PET scanners to provide early diagnosis of the disease. Therefore, we have proposed the Helmet-Chin PET, a novel geometry for highly sensitive brain imaging based on a hemispheric arrangement of detectors. For a proof-of-concept, last year we developed the first prototype using 4-layered depth-of-interaction (DOI) detectors. Following successful realization of phantom imaging, we conducted the first clinical test which we describe in this paper. Methods: The Helmet-Chin PET prototype was developed using 54 DOI detectors, each of which consisted of 16×16×4 Zr-doped GSO crystals (2.8×2.8×7.5 mm3) and a high sensitivity 64-channel flat-panel photomultiplier tube. In the prototype, 47 detectors were used to form a hemisphere of 25 cm inner diameter and 50 cm outer diameter, and 7 detectors were used for the chin detector. First of all, we compared sensitivity for the brain region with a commercial scanner to determine injection activity. We measured the count rate performance of the prototype and that of a whole-body PET, Biograph mCT Flow 64-4R PET/CT system (Siemens Medical Solutions USA, Inc.). The mCT consisted of four detector rings 84 cm in diameter, having 192 detectors, each of which consisted of 13×13 LSO crystals (4×4×20 mm3). We made a pool phantom with a shape of hemisphere with inner diameter of 20 cm filled with 18F solution. The phantom was measured with the prototype and the mCT for 5 min. Following the sensitivity assessment, we conducted the initial clinical test using the prototype. A healthy volunteer was measured for 18 min beginning 85 min after 18F-FDG injection of 70 MBq. For attenuation correction, the separately scanned CT image was registered. Results: The measured sensitivity for the brain region was 17.4 kcps/MBq for the Helmet-Chin PET prototype and 9.3 kcps/MBq for the mCT, where the energy windows were 400-600 keV and 435-650 keV, respectively. The sensitivity of the Helmet-Chin PET for the brain region was almost twice as high as that of the mCT, even though the number of detectors was less than 30% that of the mCT. For the initial clinical test, we could obtain a clear image of the brain with low radioactivity injection. Conclusions: Our initial clinical test using the first prototype showed that the Helmet-Chin PET has promising performance for highly sensitive brain imaging., SNMMI 2016

Occupational accidents and injuries have health, economic, social and psychological impacts like Post-Trau- matic Stress Disorder (PTSD) which is develops after a traumatic event. This is study including 363 workers referred to the centers due to exposure to a workplace accident or injury. Cronbach alpha coefficient was calculated to assess the reli- ability of the check lists for psychometric properties: Post-traumatic Stress Disorder Checklist Civilian version, Hamilton Anxiety Scale and Trauma Symptom Checklist. Most of participants are males of age (30 - 40) years. The prevalence of (PTSD) reaching almost one- half of the sample and there is a significant associations between (PTSD) and worker's gender (p=0.03), nationality (p

Malnutrition in all its forms is still a major public health problem in the world, especially in developing countries, including Sudan. It’s an underlying factor in over 50% of deaths in children under five years of age who die each year from preventable causes. Malnutrition prevents children from reaching their full physical and mental potential. The Specific objective of this paper was to determine the magnitude of malnutrition among children aged 6-59 months in Tawila Administrative Unit (TAU) in Tawila locality in North Darfur State at Sudan, 2017. This paper was comparative cross-sectional community-based study applied the quantitative research method. Five-hundred and ninety seven children at the age ranged between 6-59-month were studied. To assess the malnutrition status of the children under the study, anthropometric measurements for height, weight and edema examination were applied. The collected data analyzed by using Epidemiological Information (Epi-Info), emergency nutritional assessment software version 11 (ENA). The anthropometric result was classification based on WHO standard, 2006. The results showed that the prevalence rate of wasting was 14.7% (10.4 - 20.4 95% C.I.), stunting was 48.9% (44.1 - 53.8 95% C.I.) and underweight was 35.6% (30.4 - 41.1 95% C.I.). Male children and those aged between (12 -23 months) are at higher risk of acute malnutrition and those aged (12-35 month) are at higher risk to stunting and underweight. The study concluded that the malnutrition is an important major public health problem among under five children ages in Tawila locality. Under-five children in Tawila locality suffer high rates of malnutrition. Therefore, health facility-based interventions, community-based program, nutritional education programs are strongly recommended in Tawila locality. In addition to that ensuring food security including the availability and adequacy of general rations (including iodized salt and fortified grain/cereals).

アルツハイマー型認知症などの脳疾患を発症前の早い段階で発見することが可能な診断薬の臨床応用が進められており、それに伴い頭部専用のPET（Positron Emission Tomography）装置（脳PET）の潜在的な需要が高まってきている。スクリーニング検査用の脳PETとして広く普及させるためには、1)高感度、2)高分解能、3)低コストであることが要求される。これまでにも、脳PET装置が開発されているが、それらは全てブロック検出器を円筒状に配置したものであった[1-6]。それに対して我々は、半球状の検出器配置で、ヘルメットのように近接させて頭頂部を覆うことで、同じ検出器数の円筒型PETと比較して、大脳部の感度を大幅に高められることを示した（図１）[7, 8]。さらに、あごの部分を覆うように検出器を追加することで、半球型の検出器配置のみでは円筒型配置の端部分と同様に低感度となる小脳部の感度を向上させることができる。本研究では、検出器を近接させることによる空間分解能の劣化を抑えるために、放射線医学総合研究所（放医研）で開発された4層DOI（Depth-of-Interaction）検出器[9, 10]を用いて、提案するヘルメットPETの実証機を開発した[11]。 図1 ヘルメットPETと円筒型PETの幾何学的感度解析結果 2.方法 図2に開発した実証機の写真と検出器配置の立体図を示す。ヘルメットPETは半球型のヘルメット部と、あごの周りを覆うように検出器を配置したあご部によって構成される。DOI検出器を用いて提案装置を実現するために、直径の異なる複数のリングを半球に接するように並べ、頭頂部では十字型に配置した。半球型のガントリーの内径は25 cmとした。そして、あごの部分には円弧状に配置した。DOI検出器は、高感度型の64ch光電子増倍管（PMT: Photo Multiplier Tube）（浜松ホトニクス社製R10551-00-64）と16×16×4配列のGSOZ結晶（2.8 mm×2.8 mm×7.5 mm）からなり、ヘルメット検出器47個、あご検出器7個の計54個用いた。 図2 ヘルメットPET実証機の写真と検出器配置の立体図 実証機のデータ収集システムではシングルイベントを記録し、後処理で同時計数イベントを抽出した[12]。エネルギーウィンドウは400 keVから600 keVとし、同時計数の時間窓は20 nsとした。 開発した実証機を用いて、絶対感度及び空間分解能の評価と、3次元脳ファントムを用いたイメージング性能評価を行った。絶対感度と空間分解能評価では、中心から頭頂へのオフセット毎に、0.18 MBqの22Na点線源を5分間ずつ測定した。なお、中心は16検出器からなる第一リングの中心部とした。そして、FBP（Filtered Back Projection）法とLM-OSEM（List-Mode Ordered Subset Expectation Maximization）法によって画像を再構成した。ボクセルサイズは0.5×0.5×0.5 mm3とした。FBP法のフィルタ関数はカットオフなしのRampフィルタを用いた。また、LM-OSEM法では、検出器の応答関数を考慮したシステムマトリクスを使用し、サブセット数8、反復回数10とした。 イメージング性能評価では、20 MBqの18F水溶液を3次元脳ファントム（モレキュラーイメージングラボ社製）に満たし、20分間測定した。減弱補正は事前に撮影したX線CT画像を手動で位置合わせすることで行った。偶発同時計数の補正は遅延同時計数によって行った。感度補正はガントリーの内側に合わせ、直径の異なる2つの円筒を重ねた形状のプールファントム（18F水溶液38 MBq）を12時間測定することで行った。散乱補正はヘルメットPETに適用可能なSSS（Single Scatter Simulation）法を新たに開発して適用した。 3.結果・考察 図3に絶対感度と空間分解能の評価結果を示す。装置感度は頭頂付近で10%以上、小脳部で5%であった。また、平均空間分解能（半値幅）は、FBP法で3.0 mm、LM-OSEM法で1.4 mmであった。放医研でこれまでに開発した頭部PETであるjPET-D4では、256ch PMT（浜松ホトニクス社製H9500）と16×16×4配列のGSO結晶（3.0 mm×3.0 mm×7.5 mm）からなるDOI検出器を120個用いており、中心感度は11%であったが[3]、ヘルメットPETではほぼ同程度の検出器54個で同等な最大感度を達成できることが示された。 図3 実証機の絶対感度と空間分解能 図4に3次元脳ファントムを測定し、画像再構成であご検出器に関するデータを使用した場合（あご検出器あり）と、間引いた場合（あご検出器なし）について比較した。その結果、あご検出器の追加によって、特に半球底面部のスライスのノイズが低減されることが示された。 図4 あご検出器ありとなしの場合の3次元脳ファントムの再構成像の比較（数字はスライスの位置を示す） 4.結論 ヘルメットPET実証機開発により、提案装置によって、高感度、高分解能かつ低コストな脳PET測定が実現可能なことを示した。今後、検出器配置の最適化及び、検出器の最適化によりさらなる高性能化を目指す。 参考文献 [1]L. Eriksson, et al., “The ECAT HRRT: NEMA NEC evaluation of the HRRT system, the new high-resolution research tomograph,” IEEE Trans. Nucl. Sci., vol. 49, pp. 2085–88, 2002. [2]T. Yamaya, et al., “Transaxial system models for jPET-D4 image reconstruction,” Phys. Med. Biol., vol. 50, pp. 5339–55, 2005. [3]T. Yamaya, et al., “First Human Brain Imaging by the jPET-D4 Prototype With a Pre-Computed System Matrix,” IEEE Trans. Nucl. Sci., vol 55, pp. 2482-92, 2008. [4]S. Yamamoto, et al., “Development of a Brain PET System, PET-Hat: A Wearable PET System for Brain Research,” IEEE Trans. Nucl. Sci., vol. 58, pp. 668–73, 2011. [5]S. Majewski, et al., “HelmetPET: A silicon photomultiplier based wearable brain imager,” IEEE NSS&MIC Conf. Rec., pp. 4030-4034, 2011. [6]T. Omura, et al., “Development of a High-Resolution Four-Layer DOI Detector Using MPPCs for Brain PET,” IEEE NSS&MIC Conf. Rec., pp. 3560-3563, 2012. [7]H. Tashima, et al., “A Proposed Helmet-PET with a Jaw Detector Enabling High-Sensitivity Brain Imaging,” IEEE NSS&MIC, M11-11, 2013. [8]田島英朗, 他: あご検出器付ヘルメット型PET装置の提案, 平成25年度次世代PET研究報告書: pp. 74-75, 2014 [9]T. Tsuda, et al., “A four-layer depth of interaction detector block for small animal PET,” IEEE Trans. Nucl. Sci., vol. 51, pp. 2537–2542, 2004. [10]Y. Hirano, et al, “Performance evaluation of a depth-of-interaction detector by use of position-sensitive PMT with a super-bialkali photocathode,” Radiol. Phys. Technol., vol. 7. pp. 57-66, 2014. [11]放医研プレスリリース, 2015/11/5, http://www.nirs.go.jp/information/press/2015/11_05.shtml [12]E. Yoshida, et al., “Development of a Singles-Based Scalable Data Acquisition System for the Whole-Body OpenPET,” IEEE NSS&MIC, M11-7, 2014, 次世代PET研究会 2016

There is a strong potential demand for high-sensitivity and low-cost brain positron emission tomography (PET) imaging that is applicable to early diagnosis of Alzheimer’s disease. Therefore, we have proposed a high-sensitivity dedicated brain PET geometry composed of a helmet detector having a hemisphere shape and a chin detector, which we call helmet-chin PET. Because the shape of a human head is a sphere, the hemispherical arrangement of the detectors allows closer positioning of detectors and better sensitivity than the conventional cylindrical arrangement. In addition, adding detectors around the chin position significantly improves the sensitivity at the center where the cerebellum is located. For a proof-of-concept of the helmet-chin PET, we developed the first prototype of the helmet-chin PET using 4-layer depth-of-interaction (DOI) detectors. The helmet detector for the prototype system was realized by multiple rings having different numbers of detectors and a cross-shaped part covering the top. We used in total 54 DOI detectors, each of which consisted of 1,024 GSOZ crystals with dimensions of 2.8×2.8×7.5 mm3 and a 64-ch flat-panel photomultiplier tube. In performance evaluations, we determined there were uniform spatial resolutions of 3.0 mm by an analytical method and 1.4 mm by an iterative method. Peak sensitivity was measured as 10 % at a region near the top of the head, which was almost equivalent to the central sensitivity of the cylindrical PET composed of 120 DOI detectors. Also, we performed an initial imaging test with a brain phantom and we reconstructed the images with and without the chin detector. We found the slice near the bottom of the helmet detector had strong noise without the chin detector, while the slice had good imaging performance with it, and the overall image quality was improved. Therefore, we concluded that the helmet-chin PET had high potential for realizing high-sensitivity, low-cost, and accurate brain imaging., 2015 IEEE NSS&MIC

In this work, the control system problems, the set point tracking and the periodic disturbance rejection, are considered in general and in particular for an angular velocity servo control drive-load system. The sources of the periodic disturbances are that either the drive side, the load side or both of them have angle dependent parameters, this could take place because of the working principle of the drive as in internal combustion engines, electrical (induction or permanent magnet synchronous) motors, etc., as well as in the load side e.g. eccentricity as in crankshaft or camshaft mechanisms. These types of periodic disturbances are also called self-excited periodic disturbances generated by state dependent (periodic) parameters and have been classified and modeled in this work as internal periodic disturbances. On the other hand, periodic disturbances that do not depend on any of the system states or parameters are classified and modeled as external periodic disturbances. Therefore, for analysis and design objectives, a mathematical model has been built for a rigid and flexible drive-load system with angle dependent spring, damper and moment of inertia load elements plus an external periodic disturbance source. This has led to build an identification model representing the drive-load system that consists of input to output dynamic part plus an internal and external input periodic disturbance part. Thus, an identification algorithm is used to identify this identification model. Then, by using the identified periodic disturbance parameters of the identification model, a feed-forward controller has been designed to compensate the drive-load system periodic disturbances as an add-on to an already existing set point tracking feedback controller. This algorithm has turned out to be an indirect adaptive feed-forward periodic disturbance controller. The algorithm has been tested in simulation as well as in real-time control implementation intensively with very good results. Therefore as a next step, a test platform for a drive-load system has been built up, where the load side has a crankshaft mechanism that generates state (angle) dependent oscillations. And finally, the algorithm has been implemented in a real-time controller and successfully applied on the test platform to model, identify and consequently to compensate the periodic disturbances., In dieser Arbeit wurden die Regelungssystemprobleme, die Sollwertverfolgung und die Abstoßung der periodischen Störung, im Allgemeinen und insbesondere für ein Drehzahlservoregelungsantrieb- abtriebssystem betrachtet. Die Quellen der periodischen Störungen sind, dass entweder der Antriebsseite, der Abtriebsseite oder beide Winkel abhängigen Parameter haben. Dies könnte wegen der Arbeitsweise des Antriebs zum Beispiel in Verbrennungsmotoren, Elektro (Induktions- oder Permanentmagnet-Synchron) Motoren, usw., sowie in der Abtriebsseite zum Beispiel Exzentrizität wie in Kurbel- oder Nockenwelle Mechanismen stattfinden. Diese Arten von periodischen Störungen sind ebenfalls selbsterregte periodische Störungen genannt, und sie wurden durch zustandsabhängige (periodische) Parameter erzeugt und entsprechend klassifiziert. Außerdem wurden sie in dieser Arbeit als interne periodische Störungen modelliert. Andererseits wurden periodische Störungen, die nicht auf irgendeinen Systemzustände oder Parameter abhängen, als externen periodischen Störungen eingeordnet und entsprechend modelliert. Für die Analyse und die Entwurfsziele wurde ein mathematisches Modell daher für ein starres und flexibles Antrieb-abtriebssystem mit winkelabhängigen Feder-, Dämpfer- und Trägheitsmoment-Lastelemente als auch externe periodischen Störungsquelle aufgestellt. Dies hat zu aufbauen eins Identifikationsmodells für das Antrieb-abtriebssystem durchgeführt, das von Eingang zu Ausgang dynamisches Teil sowie ein internes und externes periodisches Eingangsstörungsteil besteht. Infolgedessen wurde ein Identifikationsalgorithmus verwendet, um dieses Identifikationsmodell zu identifizieren. Dann wurde eine Vorsteuerung unter Verwendung der identifizierten periodischen Störungsparameter des Identifikationsmodells als Zusatz zu einem bereits bestehenden Rückkopplungsregler der Sollwertverfolgung entworfen, um die periodischen Störungen des Antrieb-abtriebssystems zu kompensieren. Letztendlich hat dieser Algorithmus sich als eine indirekte adaptive Vorsteuerung für die periodische Störung herausgestellt. Der Algorithmus wurde in der Simulation als auch in der Echtzeitsteuerung intensiv mit sehr guten Ergebnissen umgesetzt und geprüft. Daher und als nächster Schritt wurde eine Testplattform für ein Antrieb-abtriebssystem aufgebaut, wo die Abtriebsseite einen Kurbelwellenmechanismus aufweist, der zustand- oder winkelabhängige Schwingungen erzeugt. Und schließlich wurde der Algorithmus in einer Echtzeitsteuerung durchgeführt und erfolgreich auf der Testplattform angewandt um die periodischen Störungen des Systems zu modellieren, zu identifizieren und somit zu kompensieren.

This study aimed to establish a local reference of thyroid volume in Sudanese normal subjects using ultrasound. A total of 103 healthy subjects were studied, 28 (27.18%) females and 75 (72.82%) males. Thyroid volume was estimated usingellipsoid formula. The mean age and range of the subjects was 21.8 (19–29) years; the mean body mass index (BMI) was 22.3 (16.46–26.07) kg/m2. The overall mean volume ± SD volume of the thyroid gland for both lobes in all the patients studied was 6.44 ± 2.44 mL. The mean volume for both lobes in females and males were 5.78 ± 1.96 mL and 6.69 ± 2.56 mL, respectively. The males' thyroid volume was greater than the females'. The mean volume of the right and left lobes of the thyroid gland in males and females were 3.38 ± 1.37 mL and 3.09 ± 1.24 mL, respectively. The right thyroid lobe volume was greater than the left. The values obtained in this study were lower than those reported from previous studies.

Background: Maternal mortality ratio is one of the indicators in the MDG that is raising concern in achieving the set target of reducing the rate by two-third by 2015. Objectives: To review the maternal mortality trend and the causes of maternal deaths in Ethiopia. Methods: Review of published and unpublished documents addressing maternal mortality in Ethiopia. Result: DHS and hospital data indicate decreasing maternal mortality even though the current maternal mortality ratio is still high. The proportion of maternal deaths due to the each of the five major causes varies with time. Generally, the limited information indicates that the proportion of maternal deaths after unsafe abortion is decreasing while deaths after preeclampsia/ eclampsia are increasing. There is no grossly notable change in the proportion of deaths due to ruptured uterus/ obstructed labor, hemorrhage and sepsis. In recent studies, maternal deaths following hepatitis are not reported while deaths due to HIV are appearing. Deaths complicated by malaria are seen in certain parts of the country. The case fatality rates of preeclampsia/eclampsia and ruptured uterus/ obstructed labor are increasing. Conclusion: Even though the review is constrained by inadequate data and interpretation uncertainty of the findings, it generally indicates the urgent need of improving the quality of maternal health services; scaling up evidence based interventions; and measuring progress. [Ethiop. J. Health Dev. 2010;24 Special Issue 1:115-122]

Urinary tract infection (UTI) is a common complication of pregnancy. It may be symptomatic or asymptomatic.The aim of this cross sectional study was to identify bacterial agents and their antibiotic susceptibility pattern isolated from pregnant women with UTI attending antenatal clinic of Tikur Anbessa Specialized Hospital (TASH).Four hundred and fourteen pregnant women with asymptomatic UTI (n = 369) and symptomatic UTI (n = 45) were investigated for urinary tract infection from January to March 2005.The age range of both groups was 18 to 44 years. Bacteriological screening of mid-stream urine specimens revealed that 39/369 (10.6%) and 9/45 (20%) had significant bacteriuria in asymptomatic and symptomatic group, respectively (p = 0.10). The overall prevalence of urinary tract infection was 48/414 (11.6%). The bacterial pathogens isolated were predominantly E. coil (44%), followed by S. aureus (20%), coagulase-negative staphylococci (16%), and K. pneumoniae (8%). Others found in small in number included P. mirabilis, P. aeruginosa, Enterococcus spp. and non-Group A-beta hemolytic Streptococcus, this accounted 2% for each. The gram positive and negative bacteria accounted 40% and 60% respectively. The susceptibility pattern for gram-negative bacteria showed that most of the isolates (65% of the strains) were sensitive to amoxicillin-clavulanic acid (70%), chloramphenicol (83.3%), gentamicin (93.3%), kanamycin (93.3%), nitrofurantoin (87.7%) and trimethoprim-sulphamethoxazole (73.3%). Among the gram-positives, more than 60% of the isolates were sensitive to amoxicillin-clavulanic acid (100%), cephalothin (95%), chloramphenicol (70%), erythromycin (80%), gentamicin (85%), methicillin (83.3%), nitrofurantoin (100%) and trimethoprim-sulphamethoxazole (65%). Generally, amoxicillin-clavulanic acid, chloramphenicol, gentamicin, nitrofurantoin and trimethoprim-sulphamethoxazole were effective at least in 70% of the isolates. Multiple drug resistance (resistance two or more drugs) was observed in 74% of the isolates.Significant bacteriuria was observed in both asymptomatic and symptomatic pregnant women. Periodic studies are recommended to confirm the findings of this study and also monitor any changes in the susceptibility patterns of uropathogens causing urinary tract infection in the pregnant women.

The presence of a companion during labor and delivery benefits for both the laboring women and neonate. Continuous labor support is practiced in different parts of the world. In Ethiopia it is neither practiced well nor researched in-depth. The purpose of the study was to assess the attitude of women in response to labor support based at institutional deliveries. This is a cross-sectional study by design. Data on labor support was collected from 406 women who delivered at three University hospitals in Addis Ababa through trained nurses using a pre-tested questionnaire. The result was analyzed using EPI INFO version 6 software packages. Seventy-three percent of the study women had fear of labor mainly due to associated pain (66.1%). About 53% of them need to have a companion during labor. The reasons given for wanting companion were emotional (49.5%) information (25%) and physical (21.7%) supports. About 54% and 37% of women at labor need to have respectively their mothers and husbands as companions. The need for labor companion was significantly associated with maternal age (x/2=13.57 p=0.00) educational status (x/2=8.7 p=0.000) monthly household income (x/2=14 p=0.00) marital status (x/2=16.77 p=0.00) and mode of delivery (x/2=9.69 p=0.02). There is a need of introducing labor companion system in our labor wards. Significant proportion of women preferred their mothers as companions. Further exploratory and operational researches suggested to be done in addressing providers companion and programmatic issues to introduce policies and guidelines of labor support into labor wards. (authors)

To assess the incidence, indications and complications of destructive vaginal deliveries.Retrospective study on the incidence, methods used, and outcomes of destructive vaginal deliveries (DVDs) performed by residents in obstetrics-gynecology from 1997 to 2002.Tikur Anbessa Teaching Hospital, Addis Ababa, Ethiopia.Overall, there were 7.8 DVDs per 1000 deliveries, with an increasing trend during the five years of the study. Craniotomy was the most common (94%) DVD-procedure mainly used for cephalopelvic disproportion (CPD), accounting for 89% of the craniotomies. The proportion of craniotomy to all the DVDs used was significantly more (p-value0.05) among non-Addis Ababa residents (98.6%) than among Addis Ababa residents (87.2%). Among the 54 women with known last menstrual date, gestational ages ranged from 31 to 45 weeks with 7.4% 13% and 79.6% of them being post-term, preterm and term, respectively. Labor lasted from 8 to 96 hours. While 104 (88.8%) women had labor-duration of more than 24 hours, 65 (56%) women had duration of more than 12 hours. Fistula was significantly higher (p-value0.05) among women with labor of more than 24 hours (15.4%) than those with shorter durations (0%). Similarly, significantly higher difference (p-value0.05) was found in infection among labors of more than 24 hours (47.7%) than shorter duration (11.8%). Minor genital traumas were significantly more frequent (p-value0.05) among first-time mothers (50.6%) than multiparous (25.8%).The low use of episiotomy (7.8 %) might have contributed to the high rate of minor genital traumas. Compared to birth weight of singleton live births in Ethiopian described by various hospital based studies (Tikur Anbessa (3126 g), Jimma (3183 g) and Sidamo hospital (3243 g)), the average birth weight of the fetuses in the craniotomy group (2957 g) found in this study ivas smaller. This may indicate that, in Ethiopia, the role of small pelvic size in CPD is more important than fetal weight. To alleviate the painful and difficult travel of laboring mothers to major hospitals, training of general practitioners in destructive vaginal delivery, pre- and post procedure care need to be strengthened