We establish a highly feasible algorithm for time-optimal cornering trajectory planning (TP) for car-like mobile robots (CLMRs) based on a dynamic model that contains actuator dynamics. First, we formulate an accurate dynamic model of a robot that contains DC motor actuators; this includes steering braking (caused by the lateral force of the front steering wheel) and two types of friction (viscous and Coulomb) under a nonslip condition. Our TP algorithm can utilize the full power of the DC motor actuators within proper pulse width modulation bounds and generated torque limits. Then, we establish an algorithm for a time-optimal cornering trajectory planning for CLMRs (TOCTP-CLMR). Our algorithm divides the trajectory into five sections comprising three turnings and two translations to minimize the travel distance. Then, we utilize the quickest rotation when turning to construct the time-optimal trajectory that satisfies the bang-bang principle. In addition, simulations are performed to demonstrate the validity of this method. Finally, we conduct open-loop experiments to validate our dynamic model and a trajectory tracking experiment to demonstrate the feasibility of the TOCTP-CLMR trajectory.

We establish an efficient minimum-time cooperative task planning algorithm for robots and operators to serve clients. This problem is an extension of the multiple traveling salesman problem and the vehicle routing problem with synchronization constraints, but it is more difficult due to the cooperative tasks of the robots and operators. To find the exact minimum-time task plan with a small tree size, we propose an efficient branch-and-bound with a good initial tree and keen complementary heuristics. Our algorithm is also effective as an approximate algorithm for the many clients problem within the capacity of the computer used. The efficiency of our algorithm is revealed via case studies: telemedical service robots and planetary exploration robots.

This article analyzes the impact of political regime and state bureaucracy on policy responses to the 1997 financial crisis in Korea, Malaysia, and Thailand. The political regime type — classified broadly into democracy and authoritarianism — is found to shape the direction of policy responses by influencing the political elites' understanding on causes, processes, and consequences of the crisis, whereas the state bureaucracy — classified into hybrid and Weberian types — decides the implementation of reform plans by determining the power of big business to resist policy change, as well as the state's organizational capacity to counter that resistance. The article argues that only when the political regime is democratic and the state Weberian will comprehensive — as opposed to partial — reform succeed.

A new myth is in the making. Once held as a model of development by practitioners and theorists alike, East Asia's Newly Industrializing Countries (NICs) are now identified as an epitome of ‘crony capitalism,’ a perversely deformed system of political and economic exchange driven by rent seekers. The privileged few have allegedly captured the state to pillage banks and sabotage market forces in pursuit of rents. But imbued with Confucian norms, which Francis Fukuyama (1995) once characterized as limiting the ‘radius’ of trust to familial ties, society cannot weed out rent seekers. The emphasis on personal loyalty is held as breeding clientelistic networks, which easily degenerate into a collusion for monopoly profits. Hiding behind a profoundly opaque corporate governance structure and protected by dense political patronage networks, business firms engage in shady deals to share rents with party politicians and state bureaucrats. From this perspective, the 1997 financial crisis was a logical outcome of East Asia's exclusionary cultural proclivities, opaque institutional arrangements, and shady business practices.

December 2002 shook up South Korea's conservative establishment and its U.S. ally. Five days before the South Korean presidential election, with a quarter of the electorate still remaining undecided, leaders of nongovernmental organizations (NGOs) and religious activists staged a massive candlelight vigil in front of Seoul's city hall to protest against “unequal” provisions in South Korea's Status of Forces Agreement (SOFA) with its U.S. ally. The political rally drew some 40,000 protestors from all walks of life. Moreover, it was only one among many climaxes in a long mobilization drive launched by NGOs and “netizens” since June, when a U.S. armored vehicle driven by Sergeant Fernando Nino and Mark Walker ran over two teenage girls during a military exercise in Hyochonli. That month saw some thirty NGOs establish a national umbrella organization to demand the trial of Nino and Walker under South Korean law. Then, in December, the Catholic, Buddhist, and Protestant religious orders joined in to lend their authority to the protestors by collectively calling for the revision of SOFA to give South Korea “primary jurisdiction” over criminal cases. The radical hanchongryon university students, too, showed up in protest sites to stir up and escalate anti-American sentiments, regularly raiding U.S. military bases in Uijongbu and Yongsan and even breaking into the U.S. Embassy compound in November. But unlike the past, this intrusion of radical hanchongryon activists did not drive away presumably conservative middle-class groups from political rallies. On the contrary, the call for a SOFA revision grew louder after the U.S. military court judged Nino and Walker not guilty of negligent homicide.

This study investigated the associations among vitamin D receptor (VDR) BsmI polymorphism, calcium intake and bone strength as indicated by the broadband ultrasound attenuation (BUA) measured by calcaneal quantitative ultrasound at the left calcaneus in community-dwelling subjects with a low calcium intake. The VDR BsmI polymorphism was analysed in 335 women older than 65 years residing in rural Asan, Korea. Calcium intake was assessed with a 2 d, 24 h recall method. The distribution of genotypes was similar to that reported in other Asian populations (92 % bb, 7 % Bb and 1 % BB). The calcaneal BUA was significantly higher (P = 0·013) in the bb genotype than in the Bb or BB genotype (Bb and BB genotypes were combined due to the small number of BB subjects) in a multiple regression model after adjusting for age, body weight, height, physical activity and nutritional factors. BUA was not significantly affected by the calcium intake regardless of the genotype, cross-sectionally. The energy-adjusted average calcium intake of this population was 439·6 mg/d (432·5 mg/d for bb and 522·3 mg/d for Bb or BB), and 96 % of the subjects had dietary intakes that were less than the recommended Dietary Reference Intake for Koreans (which for calcium is 800 mg/d for women older than 65 years). In summary, the BUA in older Korean women with a low calcium intake was significantly influenced by the VDR genotype but not by the calcium intake, cross-sectionally.

Ba5Nb4O15 has shown excellent microwave dielectric properties and is under consideration as a low-temperature cofired ceramic material for advanced radio frequency (RF) applications. By combining tape casting and liquid phase upon sintering, sintered Ba5Nb4O15 thick films stacked to form laminates were produced with aligned elongated grains. This texture engineering, correlated with crystallographic orientation, provides remarkably high temperature stability of dielectric constant up to microwave frequency. Crystallographic texture arises in Ba5Nb4O15 induced by the primary consolidation process, hot pressing, and pulsed laser deposition. The dielectric anisotropy could be efficiently obtained in the textured samples, thereby enabling significant feasibility of microwave circuit designs.

We present a feature-based probabilistic map building algorithm which directly utilizes time and amplitude information of sonar in indoor environments. Utilizing additional amplitude-of-signal (AOS) obtained concurrently with time-of-flight (TOF), the amount of inclination of target can be directly calculated from a single echo, and the number of measurements can be greatly reduced with result similar to dense scanning. A set of target groups (set of hypothesized targets originated from one measurement) is used and refined by each measurement using an extended Kalman filter and Bayesian conditional probability. Experimental results in a real indoor environment are presented to show the validity of our algorithm.

Near minimum-time direct voltage control (DVC) algorithms synthesizing path-planning and path-following are proposed for wheeled mobile robots (WMRs) satisfying (i) initial and final postures and velocities as well as (ii) voltage and current constraints. To overcome nonholonomic and nonlinear properties of WMRs, we divide our control algorithm for cornering motion into three sections: TSD (Translational Section of Deceleration), RS (Rotational Section), and TSA (Translational Section of Acceleration). We developed off-line DVC algorithms using the quadratic problem with the object function minimizing the total time, where voltages to the motors are controlled directly without velocity/torque-servo modules, while satisfying the current constraints. Two methods of searching for the two control parameters (number of steps for RS MR and velocity constraint in RS β) were considered: The one is composed of one simple 1-dimensional search for β, and the other is composed of two 1-dimensional searches for MR and β which has better performance. Performances of the proposed control algorithms are validated via various simulations.

We present an efficient obstacle avoidance control algorithm for redundant manipulators using a new measure called collidability measure. Considering moving directions of manipulator links, the collidability measure is defined as the sum of inverse of predicted collision distances between links and obstacles: This measure is suitable for obstacle avoidance since directions of moving links are as important as distances to obstacles. For kinematic or dynamic redundancy resolution, null space control is utilized to avoid obstacles by minimizing the collidability measure: We present a velocity-bounded kinematic control law which allows reasonably large gains to improve the system performance. Also, by clarifying decomposition in the joint acceleration level, we present a simple dynamic control law with bounded joint torques which guarantees tracking of a given end-effector trajectory and improves a kinematic cost function such as collidability measure. Simulation results are presented to illustrate the effectiveness of the proposed algorithm.

Correlations between the strains induced by a unipolar-electric field and the strains induced by a bipolar-electric field were investigated for Pb(Mg1/3Nb2/3)O3 (PMN) and 0.9{Pb(Mg1/3Nb2/3)O3}-0.1PbTiO3 (0.9PMN- 0.1PT) relaxor ferroelectric ceramics in the temperature range of −50°C ∼ 150°C. The magnitudes of the unipolarly induced-strains are almost the same as the differences between the bipolarly induced-strains and the residual strains, which were attributed to the absence of change of spontaneous polarization direction when the unipolar-electric field is applied.

Two basic positions have framed recent debates about South Korea's remarkable economic growth. The neoclassical position traces South Korea's take-off to a set of policy reforms in 1964 and 1965 that launched the country on the path toward export-led growth (Frank, Kim, and Westphal 1975; Kuznets 1977; Krueger 1979). Policy was far from laissez-faire, but on the whole, the reforms moved Korea in a more market-oriented direction that sought to exploit Korea's comparative advantage. The “statists,” by contrast, detail the pervasive intervention of the Korean government in the economy, even after the shift toward an outward-oriented strategy. Moreover, they argue that such intervention promoted rapid economic growth (Leudde-Neurath 1985; Jones and Sakong 1980; Amsden 1989).