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Let M be a real hypersurface in a complex space form Mn(c), \({c \neq 0}\). In this paper we prove that if \({R_{\xi}(\phi A - A\phi) + (\phi A - A\phi)R_{\xi} = 0}\) holds on M, then M is a Hopf hypersurface, where \({R_{\xi}}\) is the structure Jacobi operator, A is the shape operator of M in Mn(c) and \({\phi}\) is the tangential projection of the complex structure of Mn(c). We characterize such Hopf hypersurfaces of Mn(c).

User requirements for access and authentication increase daily because of the diversification of the Internet of Things (IoT) and social structures. The increase in authentication needs requires the generation of new passwords. Users want to utilize the same passwords for memorization convenience. However, system administrators request each user to use different passwords, as well as passwords that include special symbols. Differnet passwords and including special symbols passwords seem to exceed the tolerance range within your memorization skills. It fetches a very negative consequences in terms of password management. This paper proposes a preference symbol password system that does not require memorization by users. First, a survey is conducted to prove statistical safety, and based on this, an evolution-type password system that uses preference symbols is designed. Preference symbol passwords show superiority with respect to installation cost and convenience, compared with conventional non-memorizing password systems such as biometrics, keystrokes, and mouse patterns.

[Purpose] The purpose of this study was to analyze intra-rater and inter-rater reliabilities of the make test, a manual muscle testing measurement method, using a hand-held dynamometer in Korean young adults. [Subjects and Methods] A total of 42 university students participated in this study. The make test, a manual muscle testing method, was conducted. A hand-held dynamometer was used to measure elbow joint flexion during the make test. [Results] Both intra-rater (the intraclass correlation coefficient=0.992) and inter-rater reliabilities (the intraclass correlation coefficient=0.949) were excellent, with values over 0.9. [Conclusion] The make test is a useful manual muscle testing method with high intra-rater and inter-rater reliability.

Let M be a real hypersurface in a complex space form M2(c), c \neq 0. In this paper, we prove that S f=f S on M if and only if M is pseudo-Einstein.

We prove that a real hypersurface M in complex projective space P2.C/ or complex hyperbolic space H2.C/, whose Ricci operator is -parallel and commutes with the structure tensor on the holomorphic distribution, is a Hopf hypersurface. We also give a characterization of this hypersurface. In this paper we consider a real hypersurface M in a complex space form M2.c/, c6D 0. Then M has an almost contact metric structure.; g;;/ induced from the Kahler metric and complex structure J on Mn.c/. The structure vector field is said to be principal if A D is satisfied, where A is the shape operator of M and D. A/ . In this case, it is known that is locally constant (Ki and Suh 1990) and that M is called a Hopf hypersurface. Takagi (1973) classified homogeneous real hypersurfaces in Pn.C/ into six model spaces A1, A2, B, C, D and E of Hopf hypersurfaces with constant principal curvatures. Berndt (1989) classified all homogeneous Hopf hypersurfaces in Hn.C/ as four model spaces, which are said to be A0, A1, A2 and B. A real hypersurface M of type A1 or A2 in Pn.C/ or type A0, A1 or A2 in Hn.C/ is said to be of type A for simplicity. As a typical characterization of real hypersurfaces of type A, the following is due to Okumura (1975) for c> 0, and Montiel and Romero (1986) for c< 0.

In this paper, we prove that if \((\nabla _{X} L_{\xi })Y= (\nabla _{Y} L_{\xi })X\) holds on \(M\), then \(M\) is a Hopf hypersurface, where \(L_\xi \) denote the induced operator from the Lie derivative with respect to the structure vector field \(\xi \). We characterize such Hopf hypersurfaces of \(M_n(c)\).

In this paper, we study a real hypersurface M in a non-at 2-dimensional complex space form M2(c) with η-parallel Ricci and shape operators. The characterizations of these real hypersurfaces are obtained.

Let M be a real hypersurface with almost contact metric structure ( ϕ , g , ξ , η ) in a complex space form M n ( c ) , c ≠ 0 . In this paper we prove that if R ξ ϕ A + A ϕ R ξ = 0 holds on M, then M is a Hopf hypersurface in M n ( c ) , where A denotes the shape operator, ϕ the structure tensor and R ξ the Jacobi operator with respect to the structure vector field ξ. We characterize such Hopf hypersurfaces of M n ( c ) .

Let M be a real hypersurface with almost contact metric structure (`,g,»,·) in a complex space form Mn(c), c 6 0. In this paper we prove that if R»L»g = 0 holds on M, then M is a Hopf hypersurface in Mn(c), where R» and L» denote the structure Jacobi operator and the operator of the Lie derivative with respect to the structure vector field » respectively. We characterize such Hopf hypersurfaces of Mn(c).

This study was performed to develop a system that can be used to manage safety and environmental issues efficiently in the petrochemical industry. The main objective of this study is to reduce loss in petrochemical industries using a loss control system (LCMCI; The Loss Control Management System for Continuous Improvement of the Petrochemical Industry), which can be used to improve safety and environmental management continuously in the petrochemical industries. To prevent loss by accident in this study, firstly, causes of accidents were analyzed according to frequency and severity of accidents that have occurred in domestic petrochemical industries for 30 years. Secondly, the requirements of several kinds of systems (PSM, RC, OHSAS18001, ISO14001, etc.) which were applied mandatorily/optionally in petrochemical industries were analyzed and, also, the merits/demerits of each system were compared. Thirdly, the best practices which were recommended basically as a loss control management system in the world were modified in accordance with the situation of domestic petrochemical industries. Lastly, the requirements of loss management were defined in accordance with a management structure and then LCMCI was developed by using distribution of scores as result of this study.

Objective The importance of traumatic dural venous sinus injury lies in the probability of massive blood loss at the time of trauma or emergency operation resulting in a high mortality rate during the perioperative period. We considered the appropriate methods of treatment that are most essential in the overall management of traumatic dural venous sinus injuries. Methods We conducted a retrospective review of all cases involving patients with dural venous sinus injury who presented to our hospital between January 1999 and December 2014. Results Between January 1999 and December 2014, 20 patients with a dural venous sinus injury out of the 1,200 patients with severe head injuries who had been operated upon in our clinic were reviewed retrospectively. There were 17 male and 3 female patients. In 11 out of the 13 patients with a linear skull fracture crossing the dural venous sinus, massive blood loss from the injured sinus wall could be controlled by simple digital pressure using Gelfoam. All 5 patients with a linear skull fracture parallel to the sinus over the venous sinus developed massive sinus bleeding that could not be controlled by simple digital pressure. Conclusion When there is a linear skull fracture parallel to the sinus over the dural venous sinus or a depressed skull fracture penetrating the sinus, the surgeon should be prepared for the possibility of potentially fatal venous sinus injury, even in the absence of a hematoma.

Let $M$ be a real hypersurface in a complex space form $\mn$, $c \neq 0$. In this paper we prove that if $\rx\li = \li\rx$ holds on $M$, then $M$ is a Hopf hypersurface, where $\rx$ and $\li$ denote the structure Jacobi operator and the induced operator from the Lie derivative with respect to the structure vector field $\xi$, respectively. We characterize such Hopf hypersurfaces of $\mn$.

We propose an optimum power allocation scheme for distributed antenna systems (DAS) in time-varying Rayleigh and Ricean fading channels. In the conventional power allocation schemes for DAS, channel state information (CSI) for feedback includes the fast small-scale fading. This causes two practical problems. First, tracking fast fading requires considerable extra bandwidth and processing, which becomes even larger as the number of the distributed antennas increases. Secondly, there is non-negligible power control latency due to the high Doppler of small-scale fading and the feedback loop delay. In this paper, we consider a DAS system which determines the transmission power at each distributed base stations (antennas) only based on the slowly varying large-scale fading excluding the fast small-scale fading and we derive the optimum power allocation (PA) rule for minimum BER under total power constraint. In case of even small variation in fast fading during feedback loop delay, the conventional optimum PA scheme, which includes fast small-scale fading in CSI feedback, degrades significantly and the proposed scheme achieves much lower bit error rates. Even in the case with no latency, the proposed scheme loses only about 1dB SNR compared to the optimum scheme, which includes fast fading feedback. Finally, though the proposed power allocation formula is derived assuming Rayleigh fading, we show that it can be employed to Ricean fading channels with a small line-of-sight (LOS) component with a negligible degradation.

A 64-year-old woman was referred to our hospital with a one-month history of progressive headache. Magnetic resonance imaging (MRI) showed a hemorrhagic mass adjacent to the left inferior cerebellar hemisphere associated with a peripheral rim of signal void. Angiography demonstrated an avascular mass and the provisional diagnosis was a large cavernous angioma in the cerebellum. Intraoperative findings revealed a thrombosed giant aneurysm of the left distal posterior inferior cerebellar artery (PICA). We report an unusual case of a completely thrombosed giant aneurysm simulating a large cavernous angioma in the cerebellum. The cerebellar cisternal location of the mass may be a clue for the pre-operative diagnosis of an aneurysm.

Hematomas caused by ruptured traumatic pseudoaneurysms of the middle meningeal artery (MMA) usually present with extradural hematomas, whereas intradural intraparenchymal hematomas are extremely rare. We report a case of traumatic pseudoaneurysm of the MMA giving rise to an intracerebral hematoma after head trauma. A 70-year-old man suffered a massive intracerebral temporoparietal hemorrhage after a head injury. CT angiogram of the brain revealed a large hematoma in the right middle cranial fossa extending to the right sylvian fissure. Cerebral angiogram also revealed a pseudoaneurysm of the MMA, which was successfully treated surgically. Although traumatic MMA pseudoaneurysm producing intracerebral hematoma (ICH) is rare, it should be considered as a possible cause of intracerebral hematoma.